Curved cannula instrument

ABSTRACT

A robotic surgical system is configured with rigid, curved cannulas that extend through the same opening into a patient&#39;s body. Surgical instruments with passively flexible shafts extend through the curved cannulas. Force isolation elements within the flexible shafts prevent shaft bending from affecting end effector actuation elements that extends through the shafts. The cannulas are oriented to direct the instruments towards a surgical site. Various port features that support the curved cannulas within the single opening are disclosed. Cannula support fixtures that support the cannulas during insertion into the single opening and mounting to robotic manipulators are disclosed. A teleoperation control system that moves the curved cannulas and their associated instruments in a manner that allows a surgeon to experience intuitive control is disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. patent applicationSer. No. 12/618,549 (filed Nov. 13, 2009) (disclosing “Curved Cannula”),which claims the benefit of provisional U.S. Patent Application No.61/1245,171 (filed Sep. 23, 2009)(disclosing “Curved Cannula”), both ofwhich are incorporated herein by reference.

This application may be related to the following applications: U.S.patent application Ser. No. 12/618,583 (filed Nov. 13, 2009) (disclosing“Curved Cannula Surgical System”), U.S. patent application Ser. No.12/618,598 (filed Nov. 13, 2009) (disclosing “Curved Cannula SurgicalSystem Control”), U.S. patent application Ser. No. 12/618,621 (filedNov. 13, 2009) (disclosing “Surgical Port Feature”), and U.S. patentapplication Ser. No. 12/618,631 (filed Nov. 13, 2009)(disclosing“Cannula Mounting Fixture”), all of which are incorporated herein byreference.

BACKGROUND

1. Field of Invention

Inventive aspects pertain to minimally invasive surgery, moreparticularly to minimally invasive robotic surgical systems, and stillmore particularly to minimally invasive robotic surgical systems thatwork through a single entry point into the patient's body.

2. Art

Benefits of minimally invasive surgery are well known, and they includeless patient trauma, less blood loss, and faster recovery times whencompared to traditional, open incision surgery. In addition, the use ofrobotic surgical systems (e.g., teleoperated robotic systems thatprovide telepresence), such as the da Vinci® Surgical Systemmanufactured by Intuitive Surgical, Inc. of Sunnyvale, Calif. is known.Such robotic surgical systems may allow a surgeon to operate withintuitive control and increased precision when compared to manualminimally invasive surgeries.

To further reduce patient trauma and to retain the benefits of roboticsurgical systems, surgeons have begun to carry out a surgical procedureto investigate or treat a patient's condition through a single incisionthrough the skin. In some instances, such “single port access” surgerieshave been performed with manual instruments or with existing surgicalrobotic systems. What is desired, therefore, are improved equipment andmethods that enable surgeons to more effectively perform single portaccess surgeries, as compared with the use of existing equipment andmethods. It is also desired to be able to easily modify existing roboticsurgical systems that are typically used for multiple incision(multi-port) surgeries to perform such single port access surgeries.

SUMMARY

In one aspect, a surgical system includes a robotic manipulator, acurved cannula, and an instrument with a passively flexible shaft thatextends through the curved cannula. The robotic manipulator moves thecurved cannula around a remote center of motion that is placed at anopening into a patient's body (e.g., an incision, a natural orifice) sothat the curved cannula provides a triangulation angle for the surgicalinstrument at the surgical site. In one implementation, an endoscope andtwo such curved cannulas with distal ends oriented towards a surgicalsite from different angles are used so that effective instrumenttriangulation is achieved, which allows the surgeon to effectively workat and view the surgical site.

In another aspect, the curved cannula includes a straight section and anadjacent curved section. A robotic manipulator mounting bracket iscoupled to the straight section. A second straight section may becoupled to the opposite end of the curved section to facilitatealignment of a passively flexible surgical instrument that extends outof the cannula's distal end towards a surgical site.

In another aspect, a surgical instrument includes a passively flexibleshaft and a surgical end effector coupled to the distal end of theshaft. The flexible shaft extends through a curved cannula, and a distalsection of the flexible shaft extends cantilevered beyond a distal endof the curved cannula. The distal section of the flexible shaft issufficiently stiff to provide effective surgical action at the surgicalsite, yet it is sufficiently flexible to allow it to be inserted andwithdrawn through the curved cannula. In some aspects, the stiffness ofthe distal section of the instrument shaft is larger than the stiffnessof the section of the shaft that remains in the curved section of thecannula during a surgical procedure.

In another aspect, a surgical port feature is a single body thatincludes channels between its top and bottom surfaces. The channels areangled in opposite directions to hold the straight sections of thecurved cannulas at a desired angle. The body is sufficiently flexible toallow the curved cannulas to move around remote centers of motion thatare generally located within the channels. In some aspects the portfeature also includes a channel for an endoscope cannula and/or one ormore auxiliary channels. The channels may include various seals.

In another aspect, a second port feature that includes an upper funnelportion and a lower tongue is disclosed. Channels for surgicalinstruments, such as the curved cannulas, are defined in a waist sectionthat joins the funnel portion and the tongue. In one aspect, this secondport feature is used for surgeries that require instruments to enter thepatient's body at a relatively small (acute) angle, because the portfeature helps prevent unnecessary stress between the instruments and thepatient's body and vice versa.

In another aspect, cannula mounting fixtures are disclosed. Thesefixtures support the cannulas for insertion and for docking to theirassociated robotic manipulators. In one aspect, a fixture includes armsthat hold an endoscope cannula and a curved instrument cannula. Inanother aspect, a fixture is configured as a cap that holds distal endsof an endoscope and a curved cannula. The cap is pointed to facilitateinsertion into the opening into the patient.

In another aspect, a control system for a robotic surgical system with acurved cannula is disclosed. The control system uses kinematic dataassociated with the curved cannula. To provide an intuitive controlexperience for the surgeon, the control system commands a roboticmanipulator to move the curved cannula and its instrument in response tothe surgeon's inputs at a master manipulator as if the instrument werepositioned along a straight axis that extends from the distal end of thecurved cannula, generally tangent to the distal end of the cannula'scurved section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front elevation view of a patient side cart in a roboticsurgical system.

FIG. 1B is a front elevation view of a surgeon's console in a roboticsurgical system.

FIG. 1C is a front elevation view of a vision cart in a robotic surgicalsystem.

FIG. 2A is a side elevation view of an instrument arm.

FIG. 2B is a perspective view of a manipulator with an instrumentmounted.

FIG. 2C is a side elevation view of a portion of a camera arm with acamera mounted.

FIG. 3 is a diagrammatic view of multiple cannulas and associatedinstruments inserted through a body wall so as to reach a surgical site.

FIG. 4A is a schematic view of a portion of a patient side roboticmanipulator that supports and moves a combination of a curved cannulaand a passively flexible surgical instrument.

FIG. 4B is a schematic view that shows a second patient side roboticmanipulator that supports and moves a second curved cannula andpassively flexible surgical instrument combination, added to the FIG. 4Aview.

FIG. 4C is a schematic view that shows an endoscopic camera manipulatorthat supports an endoscope, added to the FIG. 4B view.

FIG. 5 is a diagrammatic view of a flexible instrument.

FIG. 6A is a diagrammatic view of a pull/pull instrument design.

FIG. 6B is a diagrammatic view of a push/pull instrument design.

FIG. 7A is a bottom view of a force transmission mechanism.

FIG. 7B is a plan view of a force transmission mechanism used in apull/pull instrument design.

FIG. 7C is a plan view of a force transmission mechanism used in apush/pull instrument design.

FIG. 7D is a perspective view of another force transmission mechanismused in a push/pull instrument design.

FIG. 8A is a cutaway perspective view of a portion of an instrumentshaft.

FIG. 8B is a cross-sectional diagrammatic perspective view of anotherinstrument shaft design.

FIG. 8C is a cutaway perspective view of a portion of another instrumentshaft.

FIG. 8D is a diagrammatic perspective view of yet another instrumentshaft design.

FIG. 9A is an exploded perspective view of the distal end of a flexibleshaft instrument.

FIG. 9B is a cross-sectional view of the implementation depicted in FIG.9A.

FIG. 9C is a diagrammatic view of a pull/pull type end effector.

FIG. 9D is an exploded perspective view of the distal end of anotherflexible shaft instrument.

FIG. 9E is a diagrammatic view of a push/pull type end effector.

FIG. 9F is a diagrammatic perspective view of an instrument shaft endcap.

FIG. 10 is a diagrammatic view of a curved cannula.

FIG. 10A is a diagrammatic view of an aligning key feature.

FIG. 10B is a schematic view of a cannula end clearance detectionsystem.

FIGS. 11A and 11B illustrate cannula orientations.

FIG. 11C is a plan view of a robotic surgical system with manipulatorsin an example pose to position curved cannulas.

FIGS. 12A, 12B, and 12C are diagrammatic views that show an instrumentshaft running through and extending from various cannula configurations.

FIG. 13 is a schematic view that illustrates another curved cannula andflexible instrument combination.

FIG. 14A is a diagrammatic plan view of a port feature.

FIG. 14B is a diagrammatic perspective view of a port feature.

FIG. 15A is a diagrammatic cross-sectional view taken at a cut line inFIG. 14A.

FIG. 15B shows a detail of a seal depicted in FIG. 15A.

FIG. 15C is a diagrammatic cross-sectional view taken at another cutline in FIG. 14A.

FIG. 15D is a diagrammatic cross-sectional view that illustrates anelectrically conductive layer in a port feature.

FIG. 15E shows a detail of another seal.

FIG. 16A is a diagrammatic view of various skin and fascia incisions.

FIG. 16B is a diagrammatic perspective cross-sectional view of anotherport feature.

FIGS. 17A and 17B are diagrammatic views of yet another port feature.

FIGS. 18A and 18B are diagrammatic views of yet another port feature.

FIG. 19A is a perspective view of a cannula insertion/stabilizingfixture.

FIG. 19B is another perspective view of a cannula insertion/stabilizingfixture.

FIG. 19C is a diagrammatic perspective view of a cannula stabilizingfixture.

FIGS. 20A-20D are diagrammatic views that illustrate another way ofinserting cannulas.

FIG. 21 is a diagrammatic view of a curved cannula and various referenceaxes.

FIG. 22 is a diagrammatic view of a curved cannula and the distal end ofa flexible instrument with associated optical fiber strain sensors.

FIG. 23 is a diagrammatic view of a control system architecture.

DETAILED DESCRIPTION

This description and the accompanying drawings that illustrate inventiveaspects and embodiments should not be taken as limiting—the claimsdefine the protected invention. Various mechanical, compositional,structural, electrical, and operational changes may be made withoutdeparting from the spirit and scope of this description and the claims.In some instances, well-known circuits, structures, and techniques havenot been shown or described in detail in order not to obscure theinvention. Like numbers in two or more figures represent the same orsimilar elements.

Further, this description's terminology is not intended to limit theinvention. For example, spatially relative terms—such as “beneath”,“below”, “lower”, “above”, “upper”, “proximal”, “distal”, and thelike—may be used to describe one element's or feature's relationship toanother element or feature as illustrated in the figures. Thesespatially relative terms are intended to encompass different positions(i.e., locations) and orientations (i.e., rotational placements) of adevice in use or operation in addition to the position and orientationshown in the figures. For example, if a device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be “above” or “over” the other elements or features.Thus, the exemplary term “below” can encompass both positions andorientations of above and below. A device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Likewise, descriptionsof movement along and around various axes includes various specialdevice positions and orientations. In addition, the singular forms “a”,“an”, and “the” are intended to include the plural forms as well, unlessthe context indicates otherwise. And, the terms “comprises”,“comprising”, “includes”, and the like specify the presence of statedfeatures, steps, operations, elements, and/or components but do notpreclude the presence or addition of one or more other features, steps,operations, elements, components, and/or groups. Components described ascoupled may be electrically or mechanically directly coupled, or theymay be indirectly coupled via one or more intermediate components.

Elements and their associated aspects that are described in detail withreference to one embodiment may, whenever practical, be included inother embodiments in which they are not specifically shown or described.For example, if an element is described in detail with reference to oneembodiment and is not described with reference to a second embodiment,the element may nevertheless be claimed as included in the secondembodiment.

The term “flexible” in association with a mechanical structure orcomponent should be broadly construed. In essence, the term means thestructure or component can be repeatedly bent and restored to anoriginal shape without harm. Many “rigid” objects have a slight inherentresilient “bendiness” due to material properties, although such objectsare not considered “flexible” as the term is used herein. A flexiblemechanical structure may have infinite degrees of freedom (DOF's).Examples of such structures include closed, bendable tubes (made from,e.g., NITINOL, polymer, soft rubber, and the like), helical coilsprings, etc. that can be bent into various simple and compound curves,often without significant cross-sectional deformation. Other flexiblemechanical structures may approximate such an infinite-DOF piece byusing a series of closely spaced components that are similar to“vertebrae” in a snake-like arrangement. In such a vertebralarrangement, each component is a short link in a kinematic chain, andmovable mechanical constraints (e.g., pin hinge, cup and ball, livehinge, and the like) between each link may allow one (e.g., pitch) ortwo (e.g., pitch and yaw) DOF's of relative movement between the links.A short, flexible structure may serve as, and be modeled as, a singlemechanical constraint (joint) that provides one or more DOF's betweentwo links in a kinematic chain, even though the flexible structureitself may be a kinematic chain made of several coupled links.Knowledgeable persons will understand that a component's flexibility maybe expressed in terms of its stiffness.

In this description, a flexible mechanical structure or component may beeither actively or passively flexible. An actively flexible piece may bebent by using forces inherently associated with the piece itself. Forexample, one or more tendons may be routed lengthwise along the pieceand offset from the piece's longitudinal axis, so that tension on theone or more tendons causes the piece to bend. Other ways of activelybending an actively flexible piece include, without limitation, the useof pneumatic or hydraulic power, gears, electroactive polymer, and thelike. A passively flexible piece is bent by using a force external tothe piece. An example of a passively flexible piece with inherentstiffness is a plastic rod or a resilient rubber tube. An activelyflexible piece, when not actuated by its inherently associated forces,may be passively flexible. A single component may be made of one or moreactively and passively flexible portions in series.

Aspects of the invention are described primarily in terms of animplementation using a da Vinci® Surgical System (specifically, a ModelIS3000, marketed as the da Vinci® Si™ HD™ Surgical System), manufacturedby Intuitive Surgical, Inc. of Sunnyvale, Calif. Knowledgeable personswill understand, however, that inventive aspects disclosed herein may beembodied and implemented in various ways, including robotic andnon-robotic embodiments and implementations. Implementations on daVinci®Surgical Systems (e.g., the Model IS3000; the Model IS2000,marketed as the da Vinci® S™ HD™ Surgical System) are merely exemplaryand are not to be considered as limiting the scope of the inventiveaspects disclosed herein.

FIGS. 1A, 1B, and 1C are front elevation views of three main componentsof a teleoperated robotic surgical system for minimally invasivesurgery. These three components are interconnected so as to allow asurgeon, with the assistance of a surgical team, perform diagnostic andcorrective surgical procedures on a patient.

FIG. 1A is a front elevation view of the patient side cart component 100of the da Vinci® Surgical System. The patient side cart includes a base102 that rests on the floor, a support tower 104 that is mounted on thebase 102, and several arms that support surgical tools (which include astereoscopic endoscope). As shown in FIG. 1A, arms 106 a,106 b areinstrument arms that support and move the surgical instruments used tomanipulate tissue, and arm 108 is a camera arm that supports and movesthe endoscope. FIG. 1A also shows an optional third instrument arm 106 cthat is supported on the back side of support tower 104 and that can bepositioned to either the left or right side of the patient side cart asnecessary to conduct a surgical procedure. FIG. 1A further showsinterchangeable surgical instruments 110 a,110 b,110 c mounted on theinstrument arms 106 a,106 b,106 c, and it shows endoscope 112 mounted onthe camera arm 108. The arms are discussed in more detail below.Knowledgeable persons will appreciate that the arms that support theinstruments and the camera may also be supported by a base platform(fixed or moveable) mounted to a ceiling or wall, or in some instancesto another piece of equipment in the operating room (e.g., the operatingtable). Likewise, they will appreciate that two or more separate basesmay be used (e.g., one base supporting each arm).

FIG. 1B is a front elevation view of a surgeon's console 120 componentof the da Vinci® Surgical System. The surgeon's console is equipped withleft and right multiple DOF master tool manipulators (MTM's) 122 a,122b, which are kinematic chains that are used to control the surgicaltools (which include the endoscope and various cannulas). The surgeongrasps a pincher assembly 124 a,124 b on each MTM 122, typically withthe thumb and forefinger, and can move the pincher assembly to variouspositions and orientations. When a tool control mode is selected, eachMTM 122 is coupled to control a corresponding instrument arm 106 for thepatient side cart 100. For example, left MTM 122 a may be coupled tocontrol instrument arm 106 b and instrument 110 a, and right MTM 122 bmay be coupled to control instrument arm 106 b and instrument 110 b. Ifthe third instrument arm 106 c is used during a surgical procedure andis positioned on the left side, then left MTM 122 a can be switchedbetween controlling arm 106 a and instrument 110 a to controlling arm106 c and instrument 110 c. Likewise, if the third instrument arm 106 cis used during a surgical procedure and is positioned on the right side,then right MTM 122 a can be switched between controlling arm 106 b andinstrument 110 b to controlling arm 106 c and instrument 110 c. In someinstances, control assignments between MTM's 122 a,122 b and arm 106a/instrument 110 a combination and arm 106 b/instrument 110 bcombination may also be exchanged. This may be done, for example, if theendoscope is rolled 180 degrees, so that the instrument moving in theendoscope's field of view appears to be on the same side as the MTM thesurgeon is moving. The pincher assembly is typically used to operate ajawed surgical end effector (e.g., scissors, grasping retractor, needledriver, and the like) at the distal end of an instrument 110.

Surgeon's console 120 also includes a stereoscopic image display system126. Left side and right side images captured by the stereoscopicendoscope 112 are output on corresponding left and right displays, whichthe surgeon perceives as a three-dimensional image on display system126. In an advantageous configuration, the MTM's 122 are positionedbelow display system 126 so that the images of the surgical tools shownin the display appear to be co-located with the surgeon's hands belowthe display. This feature allows the surgeon to intuitively control thevarious surgical tools in the three-dimensional display as if watchingthe hands directly. Accordingly, the MTM servo control of the associatedinstrument arm and instrument is based on the endoscopic image referenceframe.

The endoscopic image reference frame is also used if the MTM's areswitched to a camera control mode. In the da Vinci® Surgical System, ifthe camera control mode is selected, the surgeon may move the distal endof the endoscope by moving one or both of the MTM's together (portionsof the two MTM's may be servomechanically coupled so that the two MTMportions appear to move together as a unit). The surgeon may thenintuitively move (e.g., pan, tilt, zoom) the displayed stereoscopicimage by moving the MTM's as if holding the image in the hands.

The surgeon's console 120 is typically located in the same operatingroom as the patient side cart 100, although it is positioned so that thesurgeon operating the console is outside the sterile field. One or moreassistants typically assist the surgeon by working within the sterilesurgical field (e.g., to change tools on the patient side cart, toperform manual retraction, etc.). Accordingly, the surgeon operatesremote from the sterile field, and so the console may be located in aseparate room or building from the operating room. In someimplementations, two consoles 120 (either co-located or remote from oneanother) may be networked together so that two surgeons cansimultaneously view and control tools at the surgical site.

FIG. 1C is a front elevation view of a vision cart component 140 of theda Vinci® Surgical System. The vision cart 140 houses the surgicalsystem's central electronic data processing unit 142 and visionequipment 144. The central electronic data processing unit includes muchof the data processing used to operate the surgical system. In variousother implementations, however, the electronic data processing may bedistributed in the surgeon console and patient side cart. The visionequipment includes camera control units for the left and right imagecapture functions of the stereoscopic endoscope 112. The visionequipment also includes illumination equipment (e.g., Xenon lamp) thatprovides illumination for imaging the surgical site. As shown in FIG.1C, the vision cart includes an optional 24-inch touch screen monitor146, which may be mounted elsewhere, such as on the patient side cart100. The vision cart 140 further includes space 148 for optionalauxiliary surgical equipment, such as electrosurgical units andinsufflators. The patient side cart and the surgeon's console arecoupled via optical fiber communications links to the vision cart sothat the three components together act as a single teleoperatedminimally invasive surgical system that provides an intuitivetelepresence for the surgeon. And, as mentioned above, a secondsurgeon's console may be included so that a second surgeon can, e.g.,proctor the first surgeon's work.

FIG. 2A is a side elevation view of an illustrative instrument arm 106.Sterile drapes and associated mechanisms that are normally used duringsurgery are omitted for clarity. The arm is made of a series of linksand joints that couple the links together. The arm is divided into twoportions. The first portion is the “set-up” portion 202, in whichunpowered joints couple the links. The second portion is powered,robotic manipulator portion 204 (patient side manipulator; “PSM”) thatsupports and moves the surgical instrument. During use, the set-upportion 202 is moved to place the manipulator portion 204 in the properposition to carry out the desired surgical task. The set-up portionjoints are then locked (e.g., with brake mechanisms) to prevent thisportion of the arm from moving.

FIG. 2B is a perspective view of the PSM 204 with an illustrativeinstrument 110 mounted. The PSM 204 includes a yaw servo actuator 206, apitch servo actuator 208, and an insertion and withdrawal (“I/O”)actuator 210. An illustrative surgical instrument 110 is shown mountedat an instrument mounting carriage 212. An illustrative straight cannula214 is shown mounted to cannula mount 216. Shaft 218 of instrument 110extends through cannula 214. PSM 204 is mechanically constrained so thatit moves instrument 110 around a stationary remote center of motion 220located along the instrument shaft. Yaw actuator 206 provides yaw motion222 around remote center 220, pitch actuator 208 provides pitch motion224 around remote center 220, and I/O actuator 210 provides insertionand withdrawal motion 226 through remote center 220. The set up portion202 is typically positioned to place remote center of motion 220 at theincision in the patient's body wall during surgery and to allow forsufficient yaw and pitch motion to be available to carry out theintended surgical task. Knowledgeable persons will understand thatmotion around a remote center of motion may also be constrained solelyby the use of software, rather than by a physical constraint defined bya mechanical assembly.

Matching force transmission disks in mounting carriage 212 andinstrument force transmission assembly 230 couple actuation forces fromactuators 232 in PSM 204 to move various parts of instrument 110 inorder to position, orient, and operate instrument end effector 234. Suchactuation forces may typically roll instrument shaft 218 (thus providinganother DOF through the remote center), operate a wrist 236 thatprovides yaw and pitch DOF's, and operate a movable piece or graspingjaws of various end effectors (e.g., scissors (cautery or non-cauterycapable), dissectors, graspers, needle drivers, electrocautery hooks,retractors, clip appliers, etc.).

FIG. 2C is a side elevation view of a portion of a camera arm 108 withan illustrative camera 112 mounted. Similar to the instrument arm 106,the camera arm 108 includes a set-up portion 240 and a manipulatorportion 242 (endoscopic camera manipulator; “ECM”). ECM 242 isconfigured similarly to PSM 204 and includes a yaw motion actuator 244,a pitch motion actuator 246, and an I/O motion actuator 248. Endoscope112 is mounted on carriage assembly 250, and endoscope cannula 252 ismounted on camera cannula mount 254. ECM 242 moves endoscope 112 aroundand through remote center of motion 256.

During a typical surgical procedure with the robotic surgical systemdescribed with reference to FIGS. 1A-2C, at least two incisions are madeinto the patient's body (usually with the use of a trocar to place theassociated cannula). One incision is for the endoscope camerainstrument, and the other incisions are for the necessary surgicalinstruments. Such incisions are sometimes referred to as “ports”, a termwhich may also mean a piece of equipment that is used within such anincision, as described in detail below. In some surgical procedures,several instrument and/or camera ports are necessary in order to providethe needed access and imaging for a surgical site. Although theincisions are relatively small in comparison to larger incisions usedfor traditional open surgery, there is the need and desire to furtherreduce the number of incisions to further reduce patient trauma and forimproved cosmesis.

Single port surgery is a technique in which all instruments used forminimally invasive surgery are passed through a single incision in thepatient's body wall, or in some instances through a single naturalorifice. Such methods may be referred to by various terms, such asSingle Port Access (SPA), Laparo Endoscopic Single-site Surgery (LESS),Single Incision Laparoscopic Surgery (SILS), One Port Umbilical Surgery(OPUS), Single Port Incisionless Conventional Equipment-utilizingSurgery (SPICES), Single Access Site Surgical Endoscope (SASSE), orNatural Orifice TransUmbilical Surgery (NOTUS). The use of a single portmay done using either manual instruments or a robotic surgical system,such as the one described above. A difficulty arises with such atechnique, however, because the single port constrains the angle atwhich a surgical instrument can access the surgical site. Twoinstruments, for example, are positioned nearly side-by-side, and so itis difficult to achieve advantageous triangulation angles at thesurgical site (triangulation being the ability for the distal ends oftwo surgical instruments to be positioned along two legs of a triangleto work effectively at a surgical site at the apex of the triangle).Further, since the instruments and endoscope enter via the sameincision, straight instrument shafts tend to obscure a large part of theendoscope's field of view. And in addition, if a robotic surgical systemis used, then the multiple manipulators may interfere with one another,due to both their size and their motions, which also limits the amountof end effector movement available to the surgeon.

FIG. 3 illustrates the difficulty of using a multi-arm robotic surgicalsystem for single port surgery. FIG. 3 is a diagrammatic view ofmultiple cannulas and associated instruments inserted through a bodywall so as to reach a surgical site 300. As depicted in FIG. 3, a cameracannula 302 extends through a camera incision 304, a first instrumentcannula 306 extends through a first instrument incision 308, and asecond instrument cannula 310 extends through a second instrumentincision 312. It can be seen that if each of these cannulas 302,306,310were to extend through the same (slightly enlarged) port 304, due to therequirement that each move around a remote center of motion and also dueto the bulk and movement of the manipulators described above that holdthe cannulas at mounting fittings 302 a,306 a,310 a, then very littlemovement of the instrument end effectors is possible, and the cannulasand instrument shafts can obscure the surgical site in the endoscope'sfield of view. In order to regain some triangulation of the instrumentsat the surgical site, attempts have been made to cross the instrumentshafts and use the instrument wrists to provide some limitedtriangulation, but this configuration results in a “backwards” controlscheme (right side master controls left side slave instrument in theendoscope's view, and vice-versa), which is non-intuitive and so losessome of the strong benefit of intuitive telerobotic control. Straightshaft wristed manual instruments likewise require a surgeon to moveinstruments in either a crossed-hands or cross-visual “backwards” way.And in addition, for laparoscopic surgery, there is a difficulty ofmaintaining a proper pneumoperitoneum due to the multipleinstruments/cannulas placed through a single incision.

For single port surgery using manual instruments, an attempt has beenmade to use rigid, curved instrument shafts to improve triangulation.Such curved shafts typically have a compound “S” bend that inside thebody allows them to curve away from the incision and then back to thesurgical site, and outside the body to curve away from the incision toprovide clearance for the instrument handles and the surgeon's hands.These curved instruments appear to be even more difficult to use thanstraight shaft manual instruments, because the curved shafts furtherlimit a surgeon's ability to precisely move the instruments end effectoreither by moving the shaft or by using a manually operated wristmechanism. Suturing, for example, appears to be extremely difficult withsuch rigid curved shaft instruments. In addition, the surgeon's abilityto insert and withdraw such curved shaft instruments directly betweenthe incision and the surgical site is limited because of their shape.And, due to their shape, rolling a rigid curved instrument may cause aportion of the instrument shaft to contact, and possibly damage, tissuewithout the surgeon's knowledge.

For single port surgery using robotic surgical systems, methods areproposed to provide increased controllable degrees of freedom tosurgical instruments. For example, the use of telerobotically controlled“snake-like” instruments and associated controllable guide tubes hasbeen proposed as a way to access a surgical site though a singleincision. Similarly, the use of instruments with a miniature mechanicalparallel motion mechanism has been proposed. See e.g., U.S. PatentApplication Pub. No. US 2008/0065105 A1 (filed Jun. 13, 2007)(describinga minimally invasive surgical system). While such instruments mayultimately be effective, they are often mechanically complex. And, dueto their increased DOF actuation requirements, such instruments may notbe compatible with existing robotic surgical systems.

Curved Cannula System

FIG. 4A is a schematic view of a portion of a patient side roboticmanipulator that supports and moves a combination of a curved cannulaand a passively flexible surgical instrument. As depicted in FIG. 4A, atelerobotically operated surgical instrument 402 a includes a forcetransmission mechanism 404 a, a passively flexible shaft 406 a, and anend effector 408 a. Instrument 402 a is mounted on an instrumentcarriage assembly 212 a of a PSM 204 a (previously described componentsare schematically depicted for clarity). Interface discs 414 a coupleactuation forces from servo actuators in PSM 204 a to move instrument402 a components. End effector 408 a illustratively operates with asingle DOF (e.g., closing jaws). A wrist to provide one or more endeffector DOF's (e.g., pitch, yaw; see e.g., U.S. Pat. No. 6,817,974(filed Jun. 28, 2002) (disclosing “Surgical Tool Having PositivelyPositionable Tendon-Actuated Multi-Disk Wrist Joint”), which isincorporated herein by reference) is optional and is not shown. Manyinstrument implementations do not include such a wrist. Omitting thewrist simplifies the number of actuation force interfaces between PSM204 a and instrument 402 a, and the omission also reduces the number offorce transmission elements (and hence, instrument complexity anddimensions) that would be necessary between the proximal forcetransmission mechanism 404 a and the distally actuated piece.

FIG. 4A further shows a curved cannula 416 a, which has a proximal end418 a, a distal end 420 a, and a central channel 422 a that extendsbetween proximal end 418 a and distal end 420 a. Curved cannula 416 ais, in one implementation, a rigid, single piece cannula. As depicted inFIG. 4A, proximal end 418 a of curved cannula 416 a is mounted on PSM204 a′s cannula mount 216 a. During use, instrument 402 a′s flexibleshaft 406 a extends through curved cannula 416 a′s central channel 422 aso that a distal portion of flexible shaft 406 a and end effector 408 aextend beyond cannula 416 a′s distal end 420 a in order to reachsurgical site 424. As described above, PSM 204 a′s mechanicalconstraints (or, alternately, preprogrammed software constraints in thecontrol system for PSM 204 a) cause instrument 402 a and curved cannula416 a to move in pitch and yaw around remote center of motion 426located along cannula 416 a, which is typically placed at an incision inthe patient's body wall. PSM 204 a′s I/O actuation, provided by carriage212 a, inserts and withdraws instrument 402 a through cannula 416 a tomove end effector 408 a in and out. Details of instrument 402 a, cannula416 a, and the control of these two components is described below.

FIG. 4B is a schematic view that shows a second patient side roboticmanipulator that supports and moves a second curved cannula andpassively flexible surgical instrument combination, added to the FIG. 4Aview. Components of the second PSM 204 b, instrument 402 b, and curvedcannula 416 b are substantially similar to, and function in asubstantially similar manner to, those described in FIG. 4A. Curvedcannula 416 b, however, curves in a direction opposite to the directionin which curved cannula 416 a curves. FIG. 4B thus illustrates that twocurved cannulas and associated instruments, curving in oppositedirections, are positioned to extend through a single incision 428 inthe patient's body wall 430 to reach surgical site 424. Each curvedcannula initially angles away from a straight line between the incisionand the surgical site and then curves back towards the line to directthe extended instruments to the surgical site. By operating PSM's 204 aand 204 b in pitch in yaw, the distal ends 420 a,420 b of the curvedcannulas move accordingly, and therefore instrument end effectors 404 aand 404 b are moved with reference to the surgical site (andconsequently, with reference to the endoscope's field of view). It canbe seen that although the remote centers of motion for the two curvedcannula and flexible instrument combinations are not identical, they aresufficiently close enough (proximate) to one another so that they canboth be positioned at the single incision 428.

FIG. 4C is a schematic view that shows an endoscopic camera manipulatorthat supports an endoscope, added to the FIG. 4B view. Some previouslyused reference numbers are omitted for clarity. As shown in FIG. 4C, ECM242 holds endoscope 112 such that it extends through single incision428, along with the two curved cannula and flexible instrumentcombinations. Endoscope 112 extends through a conventional cannula 252supported by cannula mount 254. In some implementations, cannula 252provides insufflation to a body cavity. ECM 242 is positioned to placethe endoscope 112's remote center of motion at incision 428. As above,it can be seen that the remote centers of motion for the two curvedcannula and instrument combinations and the endoscope 112 are notidentical, but they may be positioned sufficiently close to allow all toextend through the single incision 428 without the incision being madeunduly large. In an example implementation, the three remote centers maybe positioned on approximately a straight line, as illustrated in FIG.4C. In other implementations, such as ones described below, the remotecenters are not linearly aligned, yet are grouped sufficiently close.

FIG. 4C also schematically illustrates that the PSM's 204 a,204 b andthe ECM 242 may be positioned so that each has a significantly improvedvolume in which to move in pitch and yaw without interfering with eachother. That is, if straight-shaft instruments are used, then the PSM'smust in general remain in positions near one another to keep the shaftsin a near parallel relation for effective work through a singleincision. But with the curved cannulas, however, the PSM's can be placedfarther from one another, and so each PSM can in general move within arelatively larger volume than with the straight-shaft instruments. Inaddition, FIG. 4C illustrates how the curved cannulas 416 provide animproved triangulation for the surgical instruments, so that thesurgical site 426 is relatively unobstructed in endoscope 112's field ofview 430.

FIG. 4C further illustrates that a port feature 432 may be placed inincision 428. Cannulas 416 a, 416 b, and 252 each extend through portfeature 432. Such a port feature may have various configurations, asdescribed in detail below.

FIG. 5 is a diagrammatic view of an illustrative flexible instrument 500used with a curved cannula. Instrument 500 includes a proximal end forcetransmission mechanism 502, a distal end surgical end effector 504, anda shaft 506 that couples force transmission mechanism 502 and endeffector 504. In one implementation, shaft 506 is about 43 cm long. Insome implementations, shaft 506 is passively flexible and includes threesections—a proximal section 506 a, a distal section 506 c, and a middlesection 506 b that is between proximal and distal sections 506 a,506 c.

In some implementations, the sections 506 a,506 b,506 c may be eachcharacterized by their different stiffnesses. Section 506 a is theportion of shaft 506 that extends from force transmission mechanism 502towards the curved cannula through which the other sections of shaft 506extend. Consequently, section 506 a is relatively stiff in comparison tothe other sections 506 b,506 c. In some implementations, section 506 amay be effectively rigid. Section 506 b is relatively more flexible thanthe other two sections 506 a,506 c. The majority of section 506 b iswithin the curved cannula during a surgical procedure, and so section506 b is made relatively flexible to reduce friction with the inner wallof the curved cannula, yet it is not made so flexible so that it bucklesduring insertion under manual or servocontrolled operation. Section 506c is relatively more stiff than section 506 b, because section 506 cextends from the distal end of the curved cannula. Accordingly, section506 c is made flexible enough so that it may be inserted through thebend of the curved cannula, yet it is made rigid enough to provideadequate cantilever support for end effector 504.

In some implementations, however, shaft sections 506 a-506 c each havethe same physical structure—each being composed of the same material(s),and the material(s) chosen to have a bending stiffness acceptable foreach section—so the sections thus have the same stiffness. Suchinstrument shafts are generally lower cost because, e.g., they havefewer parts and are easier to assemble.

For instruments that require an end effector roll DOF via shaft roll,all three sections 506 a-506 c are torsionally rigid enough to transmitroll motion from the proximal end of the instrument to distal surgicalend effector 504. Examples are described in reference to FIGS. 8A-8D,below.

In some implementations, the stiffness of the instrument shaft (or atleast the portion of the shaft that moves within the cannula), with anouter material selected to reasonably minimize shaft friction within thecannula, is close to the maximum that the robot can insert and roll.Such insertion and roll forces are substantially more than forces thatcan be reasonably controlled by a human, and so the stiffness of theinstrument's distal section that extends from the distal end of thecannula can be made substantially higher than hand-operated instrumentshaft stiffness would be for a similar but manually actuated curvedcannula system. This characteristic enables the use of a curved cannularobotic surgical system in situations in which hand-operated instrumentsacting through curved cannulas may be marginally functional ornon-functional (e.g., the hand-operated shaft stiffness is too low toenable the instrument to effectively work at the surgical site). And so,in some implementations, the instrument shaft is “tuned” (e.g., byselecting one or more particular materials and/or by various shaftconstructions using the selected material(s)) to (i) make effective useof the robot's insertion and roll drive capabilities with reasonablystiff shafts while (ii) not allowing the friction between suchreasonably stiff shafts and a particular cannula curve dimension tooffset the robot's drive capability benefits. Thus certain instrumentsmay have flexible shafts of one stiffness for use with cannulas with onecurve radius and/or inner diameter, and other instruments may haveshafts of another stiffness for use with cannulas with another curveradius and/or inner diameter. For example, for a particular shaftdiameter and assuming cannula curve radius and cannula-shaft frictionvary inversely, shaft stiffness for an instrument designed for use witha cannula having a relatively larger curve radius may be larger thanshaft stiffness for an instrument designed for use with a cannula havinga relatively smaller curve radius. In various aspects, the shaft'slateral (bending) stiffness is in a range from about 1 lb-int (PSI×in⁴)to about 4 lb-int, and in one implementation the shaft's lateralstiffness is about 2.0 lb-int. In various aspects, the shaft'srotational stiffness is larger than about 11 lb-int, and in oneimplementation the shaft's rotational stiffness is about 22.0 lb-int.For shaft implementations with a lateral stiffness in the ˜1-4 lb-intrange, a practical range of rotational stiffness is in the range ofabout 11 lb-int to about 66 lb-int.

Primarily due to friction, as the bend radius of a curved cannuladecreases, instrument shaft stiffness must also decrease. If anisotropic material is used for the instrument shaft, such as isillustrated in association with FIGS. 8C and 8D, then the stiffness ofthe shaft portion that extends from the cannula's distal end is alsoreduced. At some point, either the stiffness of the shaft's extendeddistal end or the stiffness of the shaft portion between thetransmission mechanism and the cannula may become unacceptably low.Therefore, as described above, a range of stiffnesses may be defined foran isotropic material shaft of fixed dimensions, depending on acannula's bend radius and inner diameter.

Surgical instrument end effectors placed at the distal end of theflexible shaft instruments are of two general types. The first type ofend effector has no moving parts. Such non-moving end effectors mayinclude, for example, suction/irrigation tips, electrocautery hooks orblades, probes, blunt dissectors, cameras, retractors, etc. The secondtype of end effector has at least one moving component that is actuatedunder robotic control. Such moving component end effectors include, forexample, graspers, needle drivers, moving cautery hooks, clip appliers,shears (both non-cautery and cautery), etc.

The one or more moving end effector components may be actuated invarious ways. In one aspect, two tension elements may be used to actuatean end effector component. In such a “pull/pull” design, one tensionelement moves the end effector component in one direction, and thesecond tension element moves the component in the opposite direction. Inanother aspect, a single compression/tension element is used to move theend effector component. In such a “push/pull” design, pulling (tension)is used to move the component in one direction, and pushing(compression) is used to move the component in the opposite direction.In some implementations, the tension force is used to actuate the endeffector component in the direction that requires the highest force(e.g., closing jaws).

FIG. 6A is a diagrammatic view that illustrates aspects of a pull/pullinstrument design. As shown in FIG. 6A, an instrument force transmissionmechanism 602 is coupled to a grip-type end effector 604 by a flexibleshaft body 606. A tension element 608 is routed through shaft body 606and couples a movable component in end effector 604 to a component (notshown; see below) in transmission mechanism 602 that receives a roboticactuation force. Tension element 608 is routed through a force isolationcomponent 610 that is coupled between the base 612 of the end effectorand backing plate 614 in transmission mechanism 602. In oneimplementation, shaft body 606 is a plastic tube (e.g.,polyaryletheretherketone (PEEK)), tension element 608 is a hypotube(e.g., 316 Stainless Steel (face hardened), 0.028-inch OD×0.020 ID, withpolytetrafluoroethylene (PTFE) dip coating) with cables (e.g.,0.018-inch tungsten) at each end that are coupled to the transmissionmechanism and end effector components, and force isolation component 610is a coil tube (e.g., 300 series stainless steel). In one implementation304V (vacuum arc remelt) stainless steel is used, because its surfacefinish is relatively smoother than other 300 series stainless steels,which results in a lower friction for the interior of the coil tube. Itcan be seen that shaft body 606 does not experience the tension load ontension element 608 that moves the end effector component, because thetension force is offset by an equal and opposite reaction force inisolation component 610. Consequently, two such tension element andforce isolation component pairs within shaft body tube 606 can be usedfor a pull/pull end effector actuation design, the instrument shaftremains flexible with no effective change in its designed stiffness orbend during pull/pull actuation, and the tension load on tension element608 is effectively independent of shaft body 606 bending.

FIG. 6B is a diagrammatic view that illustrates aspects of a push/pullinstrument design. As shown in FIG. 6B, an instrument force transmissionmechanism 620 is coupled to a grip-type end effector 622 by a flexibleshaft body 624. A compression/tension drive element 626 is routedthrough shaft body 624 and couples a movable component in end effector622 to a component (not shown; see below) in transmission mechanism 620that receives a robotic actuation force. One or more force isolationcomponents 628 (an illustrative two are shown) are also routed throughshaft body 624 and are coupled to the base 630 of the end effector andto a backing plate 632 in the force transmission mechanism. In oneimplementation, shaft body 624 is a plastic tube (e.g., PEEK), driveelement 626 is a solid rod (e.g., 304V Stainless Steel, 0.032-inch ODwith PTFE spray coating), and force isolation components 628 are alsosolid rods (e.g., 304V Stainless Steel, 0.032-inch OD with PTFE spraycoating). It can be seen that shaft body 624 does not experience eitherthe compression or tension loads on drive element 626 that moves the endeffector component, because the drive forces are offset by equal andopposite reaction forces in isolation components 628. Consequently, theinstrument shaft remains flexible with no effective change in itsdesigned stiffness or bend during push/pull actuation, and the driveloads on drive element 626 are effectively independent of shaft body 624bending. In addition to stiffening the instrument shaft along itslongitudinal axis to isolate the push/pull drive loads, the forceisolation components 628 can act to effectively increase the instrumentshaft's bending stiffness a desired value.

FIG. 7A is a bottom view of an implementation of force transmissionmechanism 502. As shown in FIG. 7A, the force transmission mechanism ofa surgical instrument used in a da Vinci® Surgical System has beenmodified to eliminate the mechanisms used to control a wrist mechanismon the instrument and to control the jaw of an end effector (or othermoveable part) using only a single interface disk. Thus in oneillustrative implementation, one interface disk 702 a rolls shaft 506 soas to provide a roll DOF for end effector 504, and a second interfacedisk 702 b operates end effector 504's jaw mechanism. As describedabove, in one implementation a bulkhead in transmission mechanism 502supports coil tubes that run through the instrument shaft, as describedin detail above and below. Force transmission mechanism 502 may becoupled to PSM 204 without any mechanical modifications required to thePSM, a feature that minimizes implementation costs of curved cannulaaspects in existing robotic surgical systems.

FIG. 7A also shows that implementations of force transmission mechanism502 may include electrically conductive interface pins 704 and anelectronic data memory 706 that is electrically coupled to interfacepins 704. Parameters relevant to instrument 500 and its operation (e.g.,number of times the instrument has been used, Denavit-Hartenbergparameters for control (described below), etc.) may be stored in memory706 and accessed by the robotic surgical system during operation toproperly use the instrument (see e.g., U.S. Pat. No. 6,331,181 (filedOct. 15, 1999)(disclosing surgical robotic tools, data architecture, anduse), which is incorporated herein by reference). In one implementation,kinematic data specific to the curved cannula through which theinstrument extends may also be stored in memory 706, so that if thesystem detects that a curved cannula is mounted (see e.g., FIG. 10 andassociated text below), the system may access and use the stored cannuladata. If more than one curved cannula kinematic configuration (e.g.,different lengths, bend radii, bend angles, etc.) is used, then dataspecific to each allowable configuration may be stored in the associatedinstrument's memory, and the system may access and use data for thespecific cannula configuration that is mounted. In addition, in someinstances if the robotic surgical system senses that a flexibleinstrument has been coupled to a manipulator that holds a straight,rather than curved, cannula, then the system may declare this situationto be an illegal state and prevent operation.

FIG. 7B is a plan view of an illustrative implementation of a forcetransmission mechanism used in a pull/pull instrument design. As shownin FIG. 7B, two coil tubes 730 are positioned against backing plate 732.Two tension elements 734 extend from the coil tubes, through the backingplate, and are routed to open/close capstan 736, which rotates asindicated by arrows 738 to pull on one or the other of the tensionelements. FIG. 7B also depicts an illustrative implementation of shaftroll—cross-connected helical drive gear 740 and shaft roll gear 742.Roll gear 742 is coupled (e.g., laser welded) to a stainless steeladaptor swaged over the proximal end of the flexible shaft's body tube.FIG. 7B further depicts an illustrative monopolar electrocautery energyconnection 744 between plug 746 and electrically conductive tensionelements 734. And, FIG. 7B depicts an illustrative positioning of amemory chip 748 that contains instrument and/or associated cannula data,as described herein, and the chip's associated electrical contacts 750that connect with the surgical system through mating contacts on thePSM.

FIG. 7C is a plan view of an illustrative implementation of a forcetransmission mechanism used in a push/pull instrument design. As shownin FIG. 7C, force isolation rods 760 extend out of the proximal end ofthe flexible instrument shaft and are joined with backing plate 762.Push/pull drive element rod 764 also extends out of the proximal end ofthe instrument shaft, and further extends through backing plate 762 tobe coupled with slider 766. In this implementation, drive element rod764 is coupled with linear slider 766 using a free rolling bearing 768.This free rolling bearing prevents the drive rod from twisting when theinstrument shaft is rolled (i.e., provides an unconstrained roll DOF).Push/pull drive gear 770 is engaged with lever gear 772. Lever gear 772is coupled to slider 766 with link (offset crank) 774. As drive gear 770turns back and forth as indicated by arrows 776, slider 766 slides alongshaft 778 as indicated by arrows 780, thus moving drive element 764along the instrument shaft's longitudinal axis. The FIG. 7C shaft rollimplementation is substantially similar to the implementation describedabove with reference to FIG. 7B.

FIG. 7C also shows an illustrative flush fluid entry port 790 at theproximal end of the instrument shaft. In the depicted implementation,the flush fluid port is made part of the assembly that couples the shaftbody tube to the roll gear. Flush fluid may be directed into the port toclean components inside the shaft. For example, even though an actuatingdrive rod or cable may extend through a wipe seal at the distal end ofthe shaft, a small amount of body fluid may pass the seal and enter theinside of the shaft body.

FIG. 7D is a perspective view of another illustrative implementation ofa force transmission mechanism used in a push/pull instrument design. Asshown in FIG. 7D, two pinion drive gears 782 engage a rack gear 784between them. As depicted, the rack is round, and a flat rack may beused instead. The push/pull drive element rod is coupled to the rack(e.g., with a free rolling bearing as described above). Theimplementation depicted in FIG. 7D uses two extra drive elements andassociated interface disks (not shown; see e.g., FIG. 7A) positionedtowards the rear of the force transmission mechanism, and the driveelements rotate in opposite directions to move the rack along theinstrument shaft's longitudinal axis. This implementation design usesfewer parts, and so is less expensive and simpler to manufacture thanthe implementation shown in FIG. 7C, although this FIG. 7Dimplementation does use an extra drive element in the force transmissionmechanism's interface to the robotic manipulator. An advantage of usingmore than one drive element, however, is that the mechanism can exertmore force in comparison to using only a single, comparable driveelement (e.g., effectively two times as much if two drive elements areused).

It should be understood that principles described for moving an endeffector component may be adapted for use in instruments that include amovable wrist mechanism or other mechanism at the distal end of theinstrument shaft. Such a wrist mechanism allows an end effectororientation to be changed without changing shaft position.

Various design aspects may be used for the flexible instrument shafts.The following descriptions disclose example implementations of flexibleshafts used for instruments with a movable end effector component, andit should be understood that the principles described (e.g., ways ofstiffening) may be adapted for shafts that do not have an end effectorwith a moving component. It should also be understood that theprinciples may be adapted to instrument aspects that include a movablewrist mechanism or other mechanism at the distal end of the instrumentshaft.

FIG. 8A is a cutaway perspective view that shows an illustrativestructure of a portion of instrument shaft 506. Two tension elements 802a,802 b extend through a distal portion of shaft 506 and are coupled tooperate the end effector (shown diagrammatically; e.g., a 5 mm diameterclass surgical end effector used in da Vinci® Surgical Systeminstruments). Tension elements 802 a,802 b may be separate, or they maybe parts of the same element that, for example, wraps around a pulley inthe end effector. In one implementation, tension elements 802 a,802 bare 0.018-inch tungsten wire. As shown in FIG. 8A, proximal ends oftension elements 802 a,802 b are coupled (e.g., crimped, etc.) to distalends of second tension elements 804 a,804 b that further extendproximally through most of shaft 506. In one implementation, tensionelements 804 a,804 b are 0.032-inch stainless steel hypotubes. At theproximal end (not shown) tension elements 804 a,804 b are coupled totransmission mechanism 502 using wires coupled in a similar manner, asdescribed above.

As shown in FIG. 8A, tension elements 804 a,804 b extend through supporttubes 806 a,806 b respectively, which guide tension elements 804 a,804 band keep them from buckling or kinking within shaft 506. In oneimplementation, support tubes 806 a,806 b are stainless steel (e.g.,304V (vacuum melt that reduces friction)) coil tubes (0.035-inch innerdiameter; 0.065-inch outer diameter), and other materials and structuresmay be used. To reduce friction as each tension element slides insideits support tube, a friction reducing sheath 808 a,808 b is placedbetween the tension element and the inner wall of the support tube. Inone implementation, sheaths 808 a,808 b are PTFE, and other materialsmay be used. Both support tubes 806 a,806 b are placed within a singleinner shaft tube 810. In one implementation, a flat-spiral stainlesssteel wire is used for inner shaft tube 810 to provide torsionalstiffness during roll. An outer shaft tube 812 (e.g., braided stainlesssteel mesh or other material suitable to protect the shaft components)surrounds inner shaft tube 810. An elastomer skin 814 (e.g.,Pellothane®, or other suitable material) surrounds the outer shaft tube812. Skin 814 protects the inner components of shaft 506 from directcontamination by, e.g., body fluids during surgery, and the skinfacilitates shaft 506 sliding within the curved cannula. In someimplementations shaft 506 is approximately 5.5 mm (0.220 inches) outerdiameter.

In one example implementation, the support tube and tension elementassemblies may be dip coated in PTFE to provide a “sheath” that reducesfriction. The space between the coils is filled in by the dip coatingmaterial to form a tube. In another example implementation, wire ispre-coated before the coil is wound, and the coil is then baked tore-melt the coating and form the solid tube. The ends of the tube may besealed around the tension elements to prevent contamination (e.g., bodyfluids) from entering between the tension element and the coil tube.

Shaft 506 may include additional components. As shown in FIG. 8, forexample, in some implementations one or more stiffening rods 816 runthrough various portions of shaft 506. The number, size, and compositionof rods 816 may be varied to provide the various stiffnesses of portions506 a-506 c, as described above. For example, in some implementationsrods 816 are stainless steel. In addition, some implementations one ormore additional rods 818 of another material may run through one or moreportions of shaft 506. For example, FIG. 8A shows a second rod of PEEKthat in one implementation runs through distal section 506 c to providestiffness in addition to the stiffness from rods 516. In addition, oneor more supplemental tubes to provide, e.g., suction and/or irrigationor flushing for cleaning may be included in shaft 506, either inaddition to or in place of the stiffening rods. And, additional tensionelements may be included to operate, e.g., an optional multi-DOF wristmechanism at the distal end of the instrument shaft.

FIG. 8B is a cross-sectional diagrammatic perspective view of anotherimplementation of an instrument shaft design. As shown in FIG. 8B, twohypotube tension elements 820 with PTFE coating are positioned withinforce isolation coil tubes 822. An optional fluorinated ethylenepropylene (FEP) insulation layer may surround the coil tubes. A PEEKbody tube 824 surrounds the tension elements and coil tubes, and an FEPheat shrink skin 826 surrounds the body tube. An optional flush tube 828may be placed inside body tube 824, and it is configured so thatcleaning fluid from the proximal end of the shaft travels through thecleaning tube to the distal end of the shaft, and then back through thebody tube to flush out, e.g., contaminating body fluids. The instrumentmaterials are selected, nevertheless, to allow the instrument to beautoclavable for sterilization.

FIG. 8C is a cutaway perspective view that shows another illustrativestructure of a portion of instrument shaft 506. Tension elements 830 a,830 b, 832 a, and 832 b are similar to tension elements 802 a, 802 b,804 a, and 804 d described above. The tension elements are each routedthrough individual channels in multi-channel support tube 834. In oneimplementation, tube 834 is a FEP extrusion with multiple channels 836,and other materials may be used. FEP provides a low-friction surfaceagainst which the tension elements slide. One or more stiffening rods(not shown) similar to those disclosed above may be routed throughvarious other channels 836 in support tube 834 to provide desiredstiffnesses for each of the instrument shaft sections 506 a-506 c. Aseven-channel tube 834 (six channels arranged around a central channel)is shown in FIG. 8C, and a stiffening rod or other element may beinserted into the center channel. Additional cables, e.g., to operate anoptional multi-DOF wrist mechanism at the distal end of shaft 506, maybe routed through other channels in tube 834. Alternatively, otherfunctions, such as suction and/or irrigation, may be provided throughthe channels.

FIG. 8C further shows a shaft body tube 838 (e.g., extruded PEEK orother suitable material) surrounding support tube 834 to provide axialand torsional stiffness to shaft 506. An outer skin or coating 840surrounds body tube 838 to reduce friction as shaft 506 slides insidethe curved cannula and to protect the shaft components. In oneimplementation, skin 840 is a 0.005-inch layer of FEP that is heatshrunk around body tube 838, and other suitable materials may be used.In one implementation of the structure shown in FIG. 8C, the shaft 506outer diameter is approximately 5.5 mm (0.220 inches), with a singleextrusion PEEK body tube having an outer diameter of approximately 5.0mm and an inner diameter of about 3.5 mm. PEEK is used because itsstiffness (modulus of elasticity, or Young's modulus) is low enough toallow bending with low enough radial force to limit friction inside thecurved cannula so that instrument I/O is not affected in a meaningfulway, but its modulus of elasticity is high enough to provide goodcantilever beam stiffness for the shaft distal portion 506 c thatextends beyond the distal end of the curved cannula, to resist bucklingof any portion of the shaft between the transmission mechanism and theproximal end of the cannula, and to transmit roll motion and torquealong the length of the instrument shaft with adequate stiffness andprecision.

FIG. 8D is a diagrammatic transparent perspective view that shows yetanother implementation a flexible instrument shaft design. As shown inFIG. 8D, a push/pull drive element 850 extends through a center channel852 in a multi-channel tube 854, which is similar to tube 834 describedabove. Three force isolation/stiffening rods 856 as described aboveextend through three of the channels 858 surrounding the center channel.As shown in FIG. 8D, the distal ends of the rods 856 include stainlesssteel plugs that fit into the channels. In the depicted implementation,the remaining three channels 860 surrounding the center channel are leftopen and are used as flush fluid channels. In other implementations,however, other elements may be routed through one or more of thechannels 860. The surrounding instrument shaft body tube and skin areomitted from the drawing for clarity.

FIG. 9A is an exploded perspective view of an implementation of thedistal end of a flexible shaft instrument. As shown in FIG. 9A, two coiltubes 902 are coupled to distal end cap 904. The coil tubes arepositioned inside body tube 906 with outer skin 908 as described above(the tension elements are not shown). A tension element seal 910 isfitted into end cap 904, and the tension elements extend through seal910, which keeps fluids from entering into the coil tubes. In oneillustrative implementation, seal 910 is a molded silicone wipe seal.Adaptor cap 912 is positioned over the distal end of the body tube, andthe end effector clevis 914 is coupled to the adaptor cap.

FIG. 9B is a cross-sectional view of the implementation depicted in FIG.9A. In FIG. 9B it can be seen that end cap 904 includes ridges 916 thatenable the cap to be swaged inside body tube 906. Coil tubes 902 arepositioned against cap 904, and tension element cables 918 are routedthrough cap 904 and seal 910. Adaptor cap 912 is swaged over body tube906, and in the illustrative implementation is tapered to allow FEPheatshrink skin 908 to cover a portion of cap 912. End effector clevis914 is coupled (e.g., laser welded) to adaptor cap 912. Although notshown, a single clevis and adapter cap piece (not shown) may besubstituted for the cap 912 and clevis 914. The single piece reducesmanufacturing cost and complexity by eliminating the laser weld.

FIG. 9C is a diagrammatic view that illustrates a pull/pull type endeffector that may be at the distal end of the flexible shaftinstruments. As depicted in FIG. 9C, pulling on one cable opens the endeffector jaws, and pulling on the other cable closes the end effectorjaws.

FIG. 9D is an exploded perspective view of another implementation of thedistal end of a flexible shaft instrument. As shown in FIG. 9D, end cap920 fits inside the distal end of shaft body tube 922. Wipe seal 924covers the opening in end cap 920, and push/pull drive rod connector 926extends through end cap 920 and seal 924 to couple with the movablecomponent of the end effector. End effector clevis and attachment capassembly 928 fits over the end of shaft body tube 922. The componentsare assembled in a manner similar to that described in relation to FIG.9B (e.g., the use of swaging, etc.). The opening in seal 924 for thedrive rod connector is slightly undersized, and compressing the sealbefore swaging assembly 928 to the shaft body tube further closes theseal around the drive rod connector.

FIG. 9E is a diagrammatic view that illustrates a push/pull type endeffector that may be at the distal end of the flexible shaft instruments(an illustrative clip applier end effector is shown). As depicted inFIG. 9E, pushing on the drive rod closes the end effector jaws, andpulling on the drive rod opens the end effector jaws.

FIG. 9F is a diagrammatic perspective view of an implementation of anend cap designed to facilitate cleaning. Two coil tubes as describedabove are joined with the end cap at openings 940. Two flush fluid tubesas described above are joined with the end cap at openings 942. Anelongate bore 944 is placed in the end cap to intersect each of theopenings 940,942. The ends of the bore are sealed by the swageconnection between the end cap and the body tube, and so a chamber isformed (the swage ridges are omitted from the drawing for clarity).Fluid for cleaning travels distally through the instrument shaft via theflush tubes, enters the chamber, and is redirected proximally throughthe interiors of the coil tubes for cleaning. Similarly, in a push/pulltype instrument implementation, a distal end chamber receives cleaningfluid through one or more channels in a multi-channel support tube andredirects the fluid through the center channel to flush awaycontaminates for cleaning.

FIG. 10 is a diagrammatic view of an illustrative curved cannula 416. Asshown in FIG. 10, cannula 416 includes a mounting section 1002 andcannula body section 1004. The mounting section 1002 is configured to bemounted on a robotic system manipulator (e.g., PSM 204). In someimplementations, one or more features 1006 are placed on the mountingsection 1002 to be sensed by sensors 1008 in the manipulator's cannulamount. The presence of a feature 1006 as sensed by the sensors 1008 mayindicate, e.g., that the cannula is properly mounted and the type ofcannula (e.g., straight or curved, cannula length, curve radius, etc.).In one implementation the features 1006 are raised annular metal ringsand the corresponding sensors 1008 are Hall effect sensors.

Mounting section 1002 may also include a mechanical key feature 1009that mates with a corresponding feature on the manipulator to ensurethat the cannula is mounted with the proper orientation with referenceto the manipulator's insertion axis. In this way, for example, “left”and “right” curving cannulas may be made. In addition, to distinguishingleft versus right curve orientation, the keyed feature may be used toensure that the cannula is rolled at the proper angle in the manipulatormount so that instruments approach the surgical site at a desired angle.Knowledgeable persons will understand that many various mechanical keyfeatures may be used (e.g., mating pins/holes, tabs/grooves,balls/detents, and the like). FIG. 10A illustrates one example keyfeature. As shown in FIG. 10A, key feature 1030 is attached (e.g.,welded) to the side of a mounting bracket 1032 for a curved cannula. Keyfeature 1030 includes a recess 1034 that receives a portion of a roboticmanipulator's cannula mounting bracket and two vertical alignment pins1036 a and 1036 b. Alignment pins 1036 a and 1036 b mate withcorresponding alignment holes in the manipulator's mounting bracket toensure the cannula's proper roll orientation with reference to themanipulator.

FIGS. 11A and 11B are diagrammatic views of the distal ends 1102 a and1102 b of two curved cannulas as a surgeon might see them in thesurgeon's console's 3-D display 1104, which outputs images captured inthe endoscope's field of view. In the display, the curved cannulasextend away from the endoscope to enable the instruments 1106 a and 1106b to reach tissue 1108 at the surgical site. The cannulas may be mountedon the manipulators at various roll angles, or the manipulators may beoriented during surgery, so that the instruments approach the surgicalsite at various angles. Accordingly, the cannula roll orientations maydescribed in several ways. For example, the cannula roll angles may bedescribed in relation to each other. FIG. 11A shows that in oneimplementation the cannulas may be oriented with their distal curveslying approximately in a single common plane, so that the instrumentsextend from directly opposite angles towards the surgical site. FIG. 11Bshows that in one implementation the cannulas may be oriented with theirdistal curves lying in planes that are angled with reference to eachother, e.g., approximately 60 degrees as shown, so that the instrumentsextend from offset angles towards the surgical site. Many cannula curveplane relation angles are possible (e.g., 120, 90, 45, 30, or zerodegrees). Another way to express the cannula roll orientation is todefine it as the angle between the plane that includes the cannula'scurve and a plane of motion for one of the manipulator's degrees offreedom (e.g., pitch). For example, a cannula may be mounted so that itscurve lies in a plane that is angled at 30 degrees to the manipulator'spitch DOF.

Accordingly, one illustrative way to obtain the position of theinstrument cannulas as shown in FIG. 11B is to position the two PSM'sfacing one another with their pitch motion planes approximately parallel(the planes will be slightly offset so that the two cannulas do notintersect at their centers of motion). Then, each curved cannula isoriented at approximately 30 degrees with reference its correspondingPSM's pitch motion plane. FIG. 11C is a plan view of a da Vinci®Surgical System in an illustrative configuration in which two PSM's 204and the ECM 242 are posed to place curved cannulas 416 as describedabove with reference to FIG. 11B. It can be seen in FIG. 11C that, incontrast to the use of straight cannulas and instruments in a singlebody opening, the PSM's with curved cannulas have a reasonably largevolume in which they can move without collision, which provides acorrespondingly larger volume in which the instruments can move at thesurgical site.

Referring again to FIG. 10, cannula body section 1004 is in someimplementations divided into a proximal section 1004 a, a middle section1004 b, and a distal section 1004 c. Proximal section 1004 a isstraight, and its length is made sufficient to provide adequate movementclearance for the supporting PSM. Middle section 1004 b is curved toprovide the necessary instrument triangulation to the surgical site froma manipulator position that provides sufficient range of motion tocomplete the surgical task without significant collisions. In oneimplementation, middle section 1004 b is curved 60 degrees with a 5-inchbend radius. Other curve angles and bend radii may be used forparticular surgical procedures. For example, one cannula length, curveangle, and bend radius may be best suited for reaching from a particularincision point (e.g., at the umbilicus) towards one particularanatomical structure (e.g., the gall bladder) while another cannulalength, bend angle, and/or bend radius may be best suited for reachingfrom the particular incision point towards a second particularanatomical structure (e.g., the appendix). And, in some implementationstwo cannulas each having different lengths and/or bend radii may beused.

The relatively tight clearance between the curved section's inner walland the flexible instrument that slides inside requires that the curvedsection's cross-section be circular or near-circular shape throughoutits length. In some implementations the curved cannula is made of 304stainless steel (work hardened), and the curved section 1004 b is bentusing, e.g., a bending fixture or a computer numerical controlled (CNC)tube bender. For a 5.5 mm (0.220-inch) outer diameter instrument, insome implementations the curved cannula's inner diameter is made to beapproximately 0.239 inches, which provides an acceptable tolerance forinner diameter manufacturing variations that will still provide goodsliding performance for the instrument shaft.

Distal section 1004 c is a short, straight section of the cannula body.Referring to FIG. 12A, it can be seen that due to the small space (shownexaggerated for emphasis) between the instrument shaft outer diameterand the cannula inner diameter, and due to the instrument shaft'sresiliency (although passively flexible, it may retain a tendencytowards becoming straight), the distal section 1202 of the instrumentshaft contacts the outer lip of the cannula's distal end. Consequently,if the curved cannula ends at curved section 1004 b, the distal section1202 of the instrument extends out of the cannula at a relatively largerangle (again, shown exaggerated) with reference to the cannula'sextended centerline 1204. In addition, the angle between the instrumentshaft and the outer lip causes increased friction (e.g., scraping)during instrument withdrawal. As shown in FIG. 12B, however, addingdistal section 1004 c to the cannula lessens the angle between thedistal section 1202 and the cannula's extended centerline 1204 and alsolessens the friction between the outer lip and the instrument shaft.

As shown in FIG. 12C, in some implementations, a sleeve 1206 is insertedinto the distal end of distal section 1004 c. Sleeve 1206 necks down thecurved cannula's inner diameter at the distal end, and so furtherassists extending the distal section 1202 of the instrument shaft nearthe cannula's extended centerline 1204. In some implementations sleeve1206's outer lip is rounded, and sleeve 1206's inner diameter isrelatively close to the instrument shaft's outer diameter. This helpsreduce possible tissue damage by preventing tissue from being pinchedbetween the instrument shaft and the cannula during instrumentwithdrawal. In some implementations sleeve 1206 is made of 304 stainlesssteel and is approximately 0.5 inches long with an inner diameter ofapproximately 0.225 inches. Sleeve 1206 may also be made of a frictionreducing material, such as PTFE. In an alternate implementation, ratherthan using a separate sleeve 1206, the distal end of the curved cannulamay be swaged to reduce the cannula's inner diameter so as to produce asimilar effect. Other ways of necking down distal section 1004 cinclude, for example, drawing down the cannula tube or welding a smallerdiameter tube to the end of the cannula tube.

Various lengths of the straight distal section may be used to providesupport for flexible instruments at various working depths. For example,one cannula may have a curved section with a particular bend radius anda relatively shorter straight distal section, and a second cannula mayhave a curved section with the same particular bend radius but with arelatively longer straight distal section. The cannula with therelatively longer straight distal section may be used to position itsassociated instrument to reach a surgical site relatively farther withina patient, and the cannula with the relatively shorter straight distalsection may be used to position its associated instrument to reach asurgical site relatively nearer the single port entry location. Asdescribed below, control aspects of each of these identically curvedcannulas may be effectively the same, and so in some implementationseach cannula is clearly labeled (marked, color coded, etc.) to indicateto surgical personnel the length of its straight distal section.

Since various straight distal section lengths may be used for cannulaswith identical curved sections, and since these various distal sectionlengths may not be identified to the system, the system's informationabout the instrument's insertion depth within the cannula may notcorrectly identify the instrument's distal end position with referenceto a cannula's distal end. This situation may be a problem forsituations such as the use of electrocautery instruments, in which forsafety the instrument should not be energized until its distal end(i.e., the electrocautery end effector and any associated exposedenergized parts) is past the distal end of an electrically conductivecurved cannula. Therefore, in some aspects a cannula end clearancedetection system is used to determine that a distal part of aninstrument is safely beyond the distal end of the cannula.

FIG. 10B is a schematic view that illustrates one implementation of acannula end clearance detection system. As shown in FIG. 10B, a distalpart 1040 of an instrument is still within a distal straight section ofa cannula 1042. The distal part 1040 includes an electrocautery endeffector 1044, which receives electrocautery energy from energycontroller 1046. The distal part 1040 also includes a detector assembly1048, which in FIG. 10B is depicted as, e.g., an optical reflectivesensor (various other sensor types may be used, such as a Hall effectsensor). Light generated by sensor component 1050 a is reflected fromthe inner wall of cannula 1042 and is received by sensor component 1050b (there is a small gap between the instrument and the cannula, whichprovides the reflectance optical path). Energy controller 1046 iscoupled to detector assembly 1048, and so the detector assemblyindicates if the distal end of the instrument is within or past thedistal end of the cannula. As the distal end of the instrument isinserted beyond the distal end of the cannula, as indicated in dashedlines, energy controller 1046 receives an indication from detectorassembly 1048 and energizes end effector 1044. Implementations of aclearance detection system may be used for various instruments (e.g.,activation safety for laser instruments, automatic positioning ofmechanical wrist assembly for instrument withdrawal, etc.), and one ormore sensors may be placed instead on the cannula or on both theinstrument and cannula.

FIG. 13 is a schematic view that illustrates an alternate implementationof a curved cannula and flexible instrument combination. Instead of asimple C-shaped bend as described above, curved cannula 1302 has acompound S-shaped bend (either planar or volumetric). In oneillustrative implementation, each bend has about a 3-inch bend radius.Distal bend section 1304 provides triangulation for the surgicalinstrument, and proximal bend 1306 provides clearance for, e.g., PSM 204b (alternatively, in a manual implementation, for the surgicalinstrument handles and the surgeon's hands). As depicted, passivelyflexible shaft 404 b of robotically controlled surgical instrument 402 bextends through curved cannula 1302 and beyond the cannula's distal end1308. A second curved cannula and flexible instrument combination isomitted from the drawing for clarity. The use of S-shaped curvedcannulas is similar to the use of C-shaped curved cannulas as disclosedherein. For an S-shaped cannula, however, in a reference frame definedfor the endoscope's field of view, the manipulator that controls theinstrument is positioned on the same side of the surgical site as thecorresponding end effector. Since the multiple bends in the S-shapedcannula cause contact between the instrument shaft and the cannula wallat more points along the length of the cannula than the C-shapedcannula, with similar normal forces at each point, the I/O and rollfriction between the instrument and the cannula is relatively higherwith an S-shaped cannula.

The curved cannulas described herein are described as being rigid, whichmeans that they are effectively rigid during use. It is well known thatcertain materials or mechanisms may be bent into one curve shape andthen later bent again into another curve shape. For example, a flexibletube of many short links may be effectively rigidized by compressing thelinks along the tube's longitudinal axis, so that friction prevents thelinks from moving with reference to one another. Or, inner and outertubes may be radially compressed together to prevent them from slidingwith reference to one another. See e.g., U.S. Pat. No. 5,251,611 (filedMay 7, 1991)(disclosing “Method and Apparatus for Conducting ExploratoryProcedures”) and U.S. Patent Application Pub. No. US 2008/0091170 A1(filed Jun. 30, 2006)(disclosing “Cannula System for Free-SpaceNavigation and Method of Use”), both of which are incorporated herein byreference. And so, in some implementations the curved sections of thecurved cannulas as described herein may be re-bendable (repositionable)into various curve shapes. In order to determine the kinematicparameters for the curve shape, the parameters being necessary forcontrol as described below, known sensing technologies may be used. Suchtechnologies include measuring motor positions for tendons (or thedisplacements of the tendons themselves) used to re-bend the curvedsection, or the use of optical fiber shape sensing to determine thecurve shape. See e.g., U.S. Pat. No. 5,798,521 (filed Feb. 27, 1997)(disclosing “Apparatus and Method for Measuring Strain in BraggGratings”), U.S. Patent Application Pub. No. US 2006/0013523 A1 (filedJul. 13, 2005) (disclosing “Fiber Optic Position and Shape SensingDevice and Method Relating Thereto”), U.S. Patent Application Pub. No.US 2007/0156019 A1 (filed Jul. 20, 2006) (disclosing “Robotic SurgerySystem Including Position Sensors Using Fiber Bragg Gratings”), and U.S.Patent Application Pub. No. US 2007/0065077 A1 (filed Sep. 26,2006)(disclosing “Fiber Optic Position and Shape Sensing Device andMethod Relating Thereto”), all of which are incorporated herein byreference.

The various aspects and implementations described above haveconcentrated on the use of two curved cannulas to provide triangulationat the surgical site for their associated flexible shaft instruments. Insome aspects and implementations, however, a single curved cannula andits associated flexible shaft instrument may be used together with astraight cannula and its associated rigid shaft instrument. Althoughsuch an implementation provides less instrument triangulation at thesurgical site than, and may block the endoscope's surgical site image toa greater extent than, the double curved cannula implementation, thecombination of a curved and straight cannula may be beneficial or evennecessary to perform surgery in certain anatomical areas. Referring toFIG. 11C, for example, in one illustrative use of a curved cannulasurgical system, the left side PSM 204 and its associated cannula andinstrument may be temporarily removed from the single body opening, andthe additional left side PSM (shown in a partially stowed position) maybe posed to place its associated straight cannula and straight shaftinstrument into the single body opening.

Further, aspects and implementations described above have concentratedon the illustrative use of a straight, rigid endoscope. In other aspectsand implementations, however, a curved endoscope cannula may be used anda flexible shaft camera instrument may be inserted through the curvedendoscope cannula. Such a flexible shaft camera instrument may use, forexample, a flexible bundle of optical fibers to carry an image from theendoscope's distal end to a proximal end camera outside the body, or itmay have a distal end imaging system (e.g., CMOS image sensor) mountedon the end of a passively flexible shaft. As with the straight, rigidendoscope, a flexible endoscope may be inserted, withdrawn, and rolledinside its associated cannula as described herein. An advantage of usinga curved endoscope cannula is that it may provide a triangulated view ofthe surgical site that is less obstructed by surgical instruments orthat provides a move beneficial perspective of a particular tissuestructure. A straight shaft endoscope with an angled view (e.g., thirtydegrees off axis) may also be used to provide an alternate viewperspective.

Port Feature

FIG. 14A is a diagrammatic plan view of an illustrative implementationof a port feature 1402 that may be used with curved cannula andinstrument combinations, and with an endoscope and one or more otherinstruments, as described herein. FIG. 14B is a top perspective view ofthe implementation shown in FIG. 14A. Port feature 1402 is inserted intoa single incision in a patient's body wall. As shown in FIG. 14A, portfeature 1402 is a single body that has five channels that extend betweena top surface 1404 and a bottom surface 1406. Other implementations mayhave various numbers of ports in various locations on the port feature.A first channel 1408 serves as an endoscope channel and is sized toaccommodate an endoscope cannula. In alternative implementations,channel 1408 may be sized to accommodate an endoscope without a cannula.As shown in FIG. 14A, endoscope channel 1404 is offset from port feature1402's central axis 1410. If a surgical procedure requires insufflation,it may be provided via well known features on the endoscope cannula.

FIG. 14A shows two more channels 1412 a and 1412 b that serve asinstrument channels and that are each sized to accommodate a curvedcannula as described herein. Channels 1412 a,1412 b extend through portfeature 1402 at opposite angles to accommodate the positioning of thecurved cannulas. Thus, in some implementations channels 1412 a,1412 bextend across a plane that divides the port feature into left and rightsides in an orientation shown in FIG. 14A. As shown in FIG. 14A, theinstrument channels 1412 a and 1412 b are also offset from central axis1410. During use, the remote centers of motion for the endoscope andinstrument cannulas will be generally at middle vertical positionswithin their respective channels. By horizontally offsetting theendoscope channel 1408 and the instrument channels 1412 a,1412 b fromthe central axis 1410, a center point of this group of remote centerscan be positioned approximately in the center of the port feature (i.e.,in the center of the incision). Placing the remote centers closetogether minimizes patient trauma during surgery (e.g., due to tissuestretching during cannula motion). And, the port feature keeps thecannulas close to one another but resists the tendency for tissue toforce the cannulas towards one another, thus preventing the cannulasfrom interfering with one another. Various channel angles may be used invarious implementations in order to accommodate the particularconfigurations of the curved cannulas being used or to facilitate therequired curved cannula placement for a particular surgical procedure.

FIG. 14A also shows two illustrative optional auxiliary channels 1414and 1416 that extend vertically through port feature 1402 (the number ofauxiliary channels may vary). The first auxiliary channel 1414'sdiameter is relatively larger than the second auxiliary channel 1416'sdiameter (various sized diameters may be used for each auxiliarychannel). First auxiliary channel 1414 may be used to insert anothersurgical instrument (manual or robotic, such as a retractor or a suctioninstrument; with or without a cannula) through port feature 1402. Asshown in FIG. 14A, endoscope channel 1408, instrument channels 1412a,1412 b, and first auxiliary channel 1414 each include a seal(described below), and second auxiliary channel 1416 does not. And so,second auxiliary channel 1416 may likewise be used to insert anothersurgical instrument, or it may be used for another purpose better servedby not having a seal in the channel, such as to provide a channel for aflexible suction or irrigation tube (or other non-rigid instrument), orto provide a channel for insufflation or evacuation (insufflation may bedone using typical features on the endoscope cannula or other cannula).

The channel angles shown in the figures are illustrative, and it shouldbe understood that various angled channels may be used. For example, anendoscope channel may extend at an angle between the port feature's topand bottom surfaces so that an endoscope does not exert a twisting forceon the port feature during surgery (e.g., for an endoscope with athirty-degree offset viewing angle, which may be used to look “down” atthe surgical site to provide a field of view that is less obstructed bythe curved cannulas and instruments). Likewise, one or more of theauxiliary channels may be angled. And, for implementations in which oneor more curved cannulas is used in combination with a straight cannula,the straight cannula instrument channel may extend vertically betweenthe port feature's top and bottom surfaces with the curved cannulainstrument channel extending at an angle.

FIG. 14A shows that in some implementations, a port orientation feature1418 may be positioned on top surface 1404. During use, the surgeoninserts port feature 1402 into the incision and then orients the portfeature so that orientation indicator 1418 is generally in the directionof the surgical site. Thus the port feature is oriented to provide thenecessary positions for the endoscope and curved cannulas in order tocarry out the surgical procedure. Orientation feature 1418 may made invarious ways, such as molded into or printed on top surface 1404.Likewise, FIG. 14A shows that in some implementations instrument portidentification features 1420 a and 1420 b (the circled numerals “1” and“2” are shown) may be each positioned near one of the two instrumentports to identify the instrument channel. A similar identificationfeature may be placed on cannulas intended to be used on “left” or“right” sides, so that medical personnel may easily place a curvedcannula in its proper port channel by matching the cannula and portchannel identifications.

In some implementations port feature 1402 is made of a single piece ofmolded silicone (e.g., injection molded, compression molded, etc.). Theport feature may have various durometer values (e.g., in the range ofabout 40 Shore 00 (3-4 Shore A) to about 15 Shore A), and in oneillustrative implementation an injection molded silicone port featurehas a durometer value of about 5 Shore A. Other configurations of portfeature 1402 may be used, including multi-part port features withsecondary cannulas that can accommodate, e.g., both the endoscope andcurved cannulas as described herein.

Referring to FIG. 14B, in some instances the top surface 1404 and thebottom surface 1406 (not shown) are made concave. FIG. 14B also showsthat in some instances port feature 1402 is waisted. The waist 1422provides a top flange 1424 and a bottom flange 1426 that help hold portfeature 1402 in position within the incision. Since port feature 1402may be made of a soft, resilient material, the flanges 1424,1426 formedby waist 1422 and the concave top and bottom surfaces are easilydeformed to allow the surgeon to insert the port feature into theincision, and then the flanges return to their original shape to holdthe port feature in place.

FIG. 15A is a diagrammatic cross-sectional view taken at cut line A-A inFIG. 14, and it illustrates how channel 1408 b passes from the top tothe bottom surfaces at an acute angle from one side to the other acrossa vertical midsection through port feature 1402. Channel 1408 a issimilarly routed in the opposite direction. The vertical position atwhich the two channels cross (in the FIG. 15A orientation, channel 1412a (not shown) is closer to the viewer, crossing the port feature fromupper right to lower left) is approximately the vertical location of therespective cannula remote centers of motion when properly inserted. Asmentioned above, in some implementations a seal may be placed in one ormore of the channels through port feature 1402, and FIG. 15A shows anexample of such a seal illustratively positioned at or effectively atthe vertical location of the cannula remote center of motion.

FIG. 15B is a detailed view of an example implementation of a seal 1502within instrument channel 1412 b. As shown in FIG. 15B, seal 1502includes an integrally molded solid ring 1504 that extends from channel1412 b′s inner wall 1506 inwards towards channel 1412 b′s longitudinalcenterline. A small opening 1508 remains in the center of ring 1504 toallow the ring to stretch open around an inserted object, yet theopening is generally small enough to prevent any significant fluidpassage (e.g., insufflation gas escape). Thus the seals allow forinsufflation (e.g., though an auxiliary channel in the port feature)before any instruments (e.g., cannulas) are inserted. The seals alsoimprove the seal between the port feature and the cannulas when the portfeature is flexed, and the channel shapes are consequently distorted, bycannula movement during surgery. In another implementation, a thinmembrane is molded to fill the opening in the seal to provide a completeinsufflation seal until an instrument is inserted into the channel. Sucha membrane may be punctured during first cannula insertion by, e.g., anobturator.

FIG. 15C is a diagrammatic cross-sectional view taken at cut line B-B inFIG. 14A. Cut line B-B is taken through endoscope channel 1408'scenterline, and so cut line B-B does not include the auxiliary channel1414 or 1416 centerlines. FIG. 15C illustrates that in someimplementations endoscope channel 1408 includes a seal 1508, andauxiliary channel 1414 includes a seal 1510, but auxiliary channel 1416has no seal. FIG. 15C further illustrates that seals 1508 and 1510 aresimilar to seal 1502, although various seals may be used as describedabove.

FIG. 15D is a diagrammatic cross-sectional view taken at cut line A-A inFIG. 14, and it illustrates that in some implementations there is anelectrically conductive silicone layer 1512 that extends horizontallyacross the middle of the port feature (e.g., at waist 1422, as shown).The conductive layer 1512 is shown spaced midway between the portfeature's top and bottom surfaces, and so it incorporates seals asdescribed herein. In other implementations the electrically conductivelayer may be at another vertical position that does not incorporate theseals, or two or more electrically conductive layers may be used. Insome implementations, the interior of the channels are necked down atthe conductive layer but not necessarily configured as seals, so as toprovide the necessary electrical contact between the conductive layerand the instrument. In one implementation, conductive layer 1512 isintegrally molded with upper portion 1514 and lower portion 1516 of theport feature. The electrically conductive silicone may have a higherdurometer value than the upper and lower portions due to the necessaryadditives, but since it is located at approximately the level of thecannula centers of motion, the higher stiffness does not significantlyaffect cannula movement as compared to a similar port feature withoutthe electrically conductive layer. This electrically conductive layerforms an electrically conductive path between the patient's body wall,which is in contact with the port feature's outer surface, and thecannula and/or instrument that passes through the channel. Thiselectrically conductive path provides a path to electrical ground duringelectrocautery.

FIG. 15E is a detailed view of another example implementation of a sealthat may be positioned within any one of the various channels in theport feature body. As shown in FIG. 15E, an annular projection 1520 isintegrally molded with the port feature body and extends from channel1412 b′s inner wall 1506 towards the channel's centerline. In theillustrative drawing, the projection's surfaces are at about a sixtydegree angle to the channel wall, which allows an instrument to moreeasily align with and pass through the seal upon insertion. As with theseal implementation described above, the projection presses inwardsaround a cannula or other surgical instrument to provide an insufflationseal between the port feature body and the instrument. Since theprojection's cross section is generally triangular with a roundedsealing surface against the instrument, and since the instrument'sremote center of motion is generally positioned at or effectively at theseal, the seal moves with the instrument to provide a robust sealagainst the instrument as the instrument stretches the port feature bodyand slightly distorts the channel cross section during movement aroundthe remote center of motion. A small opening (e.g., 0.014 inches for aninstrument channel, 0.043 inches for an endoscope channel) remains inthe center of the seal, and in some implementations a thin membrane ismolded across this opening as described above.

Knowledgeable persons will understand that various other ways toimplement an effective seal may be used. For example, in another sealimplementation, an integrally molded resilient membrane fully blocks thechannel, and the membrane is pierced the first time an object isinserted though the channel. The membrane then forms a seal with theobject. In yet other implementations, a seal that is a separate piecemay be inserted into the channel. For instance, an annular detent may bemolded in channel wall 1506, and then a seal may be positioned and heldin the detent.

As described above, in some cases port feature 1402 may be insertedthrough the entire body wall. In other cases, however, a single incisionmay not be made through the entire body wall. For example, a singleincision may include a single percutaneous incision made at theumbilicus (e.g., in a Z shape) and multiple incisions in the underlyingfascia. Accordingly, in some cases the port feature may be eliminated,and while each of the endoscope cannula and curved cannulas extendthrough the single percutaneous incision, the cannulas each passthrough, and may be supported by, separate incisions in the fascia. FIG.16A is a diagrammatic view that illustrates portions of endoscopecannula 1602, and left and right curved cannulas 1604 a and 1604 bpassing though a single skin incision 1606, and then each throughseparate fascia incisions 1608. In some instances, operating roompersonnel may desire additional support for the cannulas in such asingle percutaneous/multiple facial incision (e.g., while docking theinserted cannulas to their associated robotic manipulators). In suchinstances, a port configured similar to top portion 1514 (FIG. 15D) orto a combined top portion 1514 and conductive layer 1512 may be used.

FIG. 16B is a diagrammatic perspective cross-sectional view of anotherport feature that may be used with a single skin incision/multiplefascia incisions procedure. Port feature 1620 is similar inconfiguration to port feature 1402, and features described above (e.g.,orientation and port indicators, seals where applicable, soft resilientmaterial, etc.) may apply to port feature 1620 as well. Port feature1620 has a body with a generally cylindrical shape that includes a topsurface 1622, a bottom surface 1624, and a narrowed sidewall waist 1626between the top and bottom surfaces. Consequently, a top flange 1628 anda bottom flange 1630 are formed between the sidewalls and the top andbottom surfaces. During use, the skin is held in the waist 1626 betweenthe upper and lower flanges, and the bottom surface 1624 and bottomflange 1630 rest on the fascia layer underlying the skin.

FIG. 16B further shows four illustrative ports that extend between theport feature's top and bottom surfaces. Channel 1632 is an endoscopechannel, and channel 1634 is an auxiliary channel, similar to suchchannels described above with reference to port feature 1402. Likewise,channels 1636 a and 1636 b are angled instrument channels that aresimilar to such channels described above, channel 1636 b angling fromtop right towards bottom left as shown, and channel 1636 a angling fromtop left towards bottom right (hidden from view). Unlike port feature1402's instrument channels, however, the centerlines of port feature1620's instrument channels 1636 a and 1636 b do not extend across theport feature's vertical midline. Instead, the angled instrument channelsstop at port feature 1620's midline, so that the remote centers ofmotion of the cannulas and instruments are positioned at the underlyingfascia incisions (an illustrative center of motion position 1638 isillustrated). Thus it can be seen that the instrument channels' exitlocations on the port feature's bottom surface may be varied so as toplace the centers of motion at a desired location with reference to apatient's tissue.

For some surgical procedures, the straight line between a singleincision and a surgical site (e.g., between the umbilicus and the gallbladder) begins to approach being at an acute angle relative to thepatient's coronal (frontal) plane. Consequently, the cannulas enter thesingle incision at a relatively small (acute) angle with reference tothe skin surface, and the body wall twists and exerts a torsion on thecannulas/instruments or on the port. FIG. 17A is a diagrammatic topview, and FIG. 17B is a diagrammatic side view, of yet another portfeature 1702 that may be used to guide and support two or more cannulasentering through a single incision. As shown in FIGS. 17A and 17B, portfeature 1702 includes an upper funnel section 1704, a lower front tongue1706, and a lower back tongue 1708. In some implementations, the funnelsection and tongues are a single piece. Port feature 1702 may be formedof for example, relatively stiff molded plastic such as PEEK,polyetherimide (e.g., Ultem® products), polyethylene, polypropylene, andthe like, so that port feature 1702 generally holds its shape duringuse. When positioned in an incision 1710, the lower tongues 1706,1708are inside the body, and the funnel section 1704 remains outside thebody. As shown in the figures, in some implementations funnel section1704 is shaped as an oblique circular or elliptical cone, which reducesinterference with equipment positioned over the funnel section when theport feature is twisted in the incision as described below. It can beseen that once in position, the distal end 1712 of funnel section 1704may be pressed towards the skin surface. This action causes the waistsection 1714 between the upper funnel portion and the lower tongues totwist in the incision, which effectively reorients the incision, and soit provides a more resistance free path to the surgical site. The fronttongue prevents port feature 1702 from coming out of the incision duringthis twisting. In addition, pushing down on distal end 1712 of thefunnel section raises the distal end 1716 of the front tongue. In someimplementations, the front tongue may be sized and shaped to retracttissue as the distal end of the tongue is raised. The back tongue 1708also helps keep port feature 1702 in the incision.

Port feature 1702 also includes at least two access channels toaccommodate endoscope and instrument cannulas. As illustrated in FIG.17A, in some implementations four example channels are within waistportion 1714. An endoscope cannula channel 1720 is placed in the middleof waist portion 1714, and three instrument cannula channels 1722 arepositioned around endoscope cannula channel 1720. In someimplementations the channels are formed in the same single piece as thefunnel section and the tongues. In other implementations, the channelsare formed in a cylindrical piece 1723 that is mounted to rotate asindicated by arrows 1723 a in waist section 1714. In someimplementations, instrument cannula channels 1722 are each formed in aball joint 1724, which is positioned in waist section 1714 (e.g.,directly, or in the cylindrical piece). The remote centers of motion ofthe cannulas are positioned in the ball joints, which then allow thecannulas to easily pivot within port feature 1702. In otherimplementations, the channels are configured to receive a ball that isaffixed (e.g. press fit) to a cannula at the remote center of motion,and the cannula ball then pivots in the channel socket as a ball joint.In some implementations, the top and bottom surfaces of the waistsection (e.g., the top and bottom surfaces of the cylindrical piece) maybe beveled to allow for increased range of motion of the cannula movingin the ball joint. In some implementations, the endoscope cannulachannel 1720 does not include a ball joint. In some implementations, anendoscope and/or instruments with rigid shafts may be routed throughtheir respective channels without cannulas, with or without the use ofball joints as described above. In some implementations, seals may bepositioned within one or more of the channels, as described above.

FIG. 18A is a diagrammatic top view, and FIG. 18B is a diagrammatic sideview, of still another port feature 1802 that may be used to guide andsupport two or more cannulas entering through a single incision. Portfeature 1802's basic configuration is similar to that of port feature1702—e.g., the funnel section, front tongue, and channels are generallysimilar. In port feature 1802, however, back tongue 1804 may be rotatedfrom a position aligned with front tongue 1806, as indicated byalternate position 1808, to a position opposite the front tongue, asshown in FIG. 18B. Therefore, back tongue 1804 may be made relativelylonger than back tongue 1708 (FIG. 17B), and port feature 1802 can stillbe inserted into a single small incision. Back tongue 1804 is alignedwith front tongue 1806 when port feature 1802 is positioned in theincision, and then it is rotated to the back position when the portfeature is in place. In one implementation, back tongue 1804 is coupledto the rotating cylinder that contains the channels, as described above,and a tab 1810, located inside the funnel section, on the cylinder pieceis rotated as indicated by the arrows from its alternate insertionposition 1812 towards the front to position the back tongue for surgicaluse.

Aspects of the port features as described herein are not confined to usewith one or more curved cannulas, and such port features may be used,for example, with straight instrument cannulas, rigid instrument shafts(with or without cannulas), and for both robotic and manual surgery.

Insertion Fixture

In multi-port minimally invasive surgery, the endoscope is typically thefirst surgical instrument to be inserted. Once inserted, the endoscopecan be positioned to view other cannula and instrument insertions sothat an instrument does not inadvertently contact and damage tissue.With a single incision, however, once an endoscope is inserted, theother cannulas and instruments are inserted at least initially outsidethe endoscope's field of view. And, for curved cannulas, it is difficultto ensure that a cannula tip will be moved directly into the endoscope'sfield of view without contacting other tissue. In addition, keeping thecannulas properly positioned and oriented as the robotic manipulatorsare adjusted and then coupled (docked) to the cannulas may requireconsiderable manual dexterity involving more than one person. Therefore,ways of safely and easily inserting multiple instruments through asingle incision are needed. During some surgical procedures, portfeatures such as those described above may provide adequate ways ofsafely inserting multiple instruments. For example, a port feature (fullor half-height) may be positioned in or on a body wall. The portfeature's channels act as guides for cannula insertion, and once thecannulas are inserted, the port feature supports the cannulas forcoupling to their associated robotic manipulators. Thus the portfeatures as described above may act as insertion and stabilizingfixtures during the early stages of a surgical procedure, as describedbelow. During other surgical procedures, or due to surgeon preference,other ways to safely insert and support multiple instruments may beused.

FIG. 19A is a perspective view of an example of a cannula insertionfixture 1902. As shown in FIG. 19A, insertion fixture 1902 is capable ofguiding an endoscope cannula and two curved instrument cannulas into asingle incision. Other implementations may guide more or fewer cannulas.Insertion fixture 1902 includes a base 1904, an endoscope cannulasupport arm 1906, and two instrument cannula support arms 1908 a and1908 b. As shown in FIG. 19A, endoscope cannula support arm 1906 isrigidly mounted on base 1904, although in other implementations it maybe pivotally mounted. The distal end of endoscope cannula support arm1906 is curved downwards toward the plane of the base and contains anendoscope cannula support slot 1910 that functions as a mounting bracketfor a cannula. Detents 1912 in support slot 1910 allow the endoscopecannula to be positioned and held at various angles.

FIG. 19A also shows that one instrument cannula support arm 1908 a ispivotally mounted on base 1904 at hinge 1914 a. An instrument cannulamount 1916 a is at the distal end of cannula support arm 1908 a andholds an illustrative instrument cannula (e.g., a curved cannula asdescribed above). Cannula mount 1916 a may include one or moremechanical key features to ensure that the cannula is held at a desiredroll orientation, as described above. FIG. 19A shows the position ofsupport arm 1908 a with its associated cannula in an inserted position.

FIG. 19A further shows that another instrument cannula support arm 1908b is pivotally mounted on base 1904 at hinge 1914 b, on a side oppositefrom support arm 1908 a. Support arm 1908 b includes an instrumentcannula mount 1916 b that is similar to cannula mount 1916 a. FIG. 19Ashows the position of support arm 1908 b with its associated cannulabefore the cannula is inserted though the incision. The cannulas areheld by the cannula mounts 1916 a,1916 b such that the axes of rotationfor the hinges 1914 a,1914 b are at approximately the axes of curvaturefor the curved cannulas. Thus, as the support arms rotate at the hinges,the curved cannulas travel through approximately the same small area,which is aligned with a single incision or other entry port into thebody. Referring to FIG. 19B, it can be seen that support arm 1908 b hasbeen moved to insert its associated cannula, which travels in an arcthrough the incision. In addition, the hinges 1914 a,1914 b may beoriented such that the two cannulas travel through slightly differentareas in the incision in order to establish a desired clearance andarrangement among the various cannulas in the incision.

An illustrative use of the cannula insertion fixture is with the singlepercutaneous/multi-fascial incision, such as one described above. Thesurgeon first makes the single percutaneous incision. Next, the surgeoninserts a dissecting (e.g., sharp) obturator into an endoscope cannulaand couples the endoscope cannula to the insertion fixture at a desiredangle. At this time the surgeon may insert an endoscope through theendoscope cannula to observe further insertions, either mounting theendoscope cannula and endoscope to a robotic manipulator or temporarilysupporting the endoscope by hand. The surgeon then many move thecannulas along their arc of insertion until they contact the body wall.Using a dissecting obturator, the surgeon may then insert each cannulathrough the fascia. The surgeon may then optionally remove thedissecting obturators from the cannulas and either leave the cannulasempty or insert blunt obturators. Then, the surgeon may continue to movethe instrument cannulas to their fully inserted positions, with theirdistal ends positioned to appear in the endoscope's field of view. Oncethe cannulas are inserted, the robotic manipulators may be moved intoposition, and the instrument cannulas may then be mounted (docked) totheir robotic manipulators. The insertion fixture is then removed, andflexible shaft instruments are inserted through the cannulas towards thesurgical site under endoscopic vision. This illustrative insertionprocedure is an example of many possible variations for using theinsertion fixture to insert and support any number of cannulas throughvarious incisions and body openings.

In some cases, an implementation of an insertion fixture may be used tosupport the cannulas while one or more manually operated instruments areinserted through the cannula(s) and used at the surgical site.

In some alternate implementations the insertion fixture may besimplified to only provide a way of holding the cannulas in a fixedposition during docking to their associated manipulators. For example,this may be accomplished by first inserting the cannulas, then applyingthe fixture to the camera cannula, and then attaching the fixture to thecurved cannulas. Once the inserted cannulas are coupled to the fixture,the patient side robot and its manipulators are moved to appropriatepositions with reference to the patient. Then, while the fixture holdsthe camera cannula and the curved cannulas in place, each cannula isdocked to its associated manipulator. Generally, the camera cannula isdocked first.

FIG. 19C is a diagrammatic perspective view of a cannula stabilizingfixture 1930. Fixture 1930 includes a base 1932 and two cannula holders1934 a and 1934 b. Arm 1936 a couples cannula holder 1934 a to base1932, and arm 1936 b couples cannula holder 1934 b to base 1932. Base1932 is coupled to a stationary object, so that the fixture can supportcannulas held at the ends of the arms. In one implementation, base 1932is configured to receive an endoscope cannula in an opening 1938, andtwo integral spring clips 1940 a and 1940 b on either side of opening1938 securely hold the base on the endoscope cannula (the endoscopecannula may be rigidly coupled to its associated ECM). Each cannulaholder 1934 a,1934 b is configured to hold an instrument cannula byreceiving a key feature similar to the key feature described above withreference to FIG. 10A. Holes in the cannula holders receive pins 1036 asshown in FIG. 10A. Arms 1936 a,1936 b are in one illustrativeimplementation heavy, bendable aluminum wire covered by silicone tubingfor corrosion resistance, and so the arms may be positioned andrepositioned as desired. In other implementations, other materials suchas stainless steel (without the need for a corrosion resistant cover orcoating) and various rebendable/repositionable configurations (e.g., arigidizable series of links as described above, a “gooseneck” type tube,etc.) may be used for the arms to provide sufficient cannula support.Each arm supports its associated cannula holder and instrument cannulaso that the instrument cannulas are held stationary with reference tothe endoscope cannula when all are positioned within a single skinincision. Knowledgeable persons will understand that many variations ofthis fixture are possible to hold the various cannulas effectively as asingle unit in position during insertion and during docking to a roboticmanipulator. For example, a single arm with cannula holders at eitherend may be used to support two cannulas with reference to one another.

FIGS. 20A-20D are diagrammatic views that illustrate another way ofinserting cannulas into a single incision. FIG. 20A shows for example anendoscope cannula 2002 and two curved cannulas 2004 a and 2004 b. Insome instances, an endoscope 2006 may be inserted in endoscope cannula2002. The distal ends of the cannulas, and if applicable the imaging endof an endoscope, are grouped together inside a cap 2008. In someimplementations the cap 2008 may be a right circular cone made of amaterial sufficiently rigid to function as an obturator to penetrate abody wall. In some implementations, a surgeon first makes an incision,and then cap 2008 with the cannulas grouped behind it is insertedthrough the incision. In some instances the cap may be made of atransparent material that allows the endoscope to image the insertionpath in front of the cap. In some implementations, cap 2008 may begrouped together with a port feature 2010, such as one described aboveor other suitable port feature. Thus in some instances the port featuremay function as one or more of the cannulas for the endoscope and/orinstruments. (As shown, port feature 2010 also illustrates thatinsufflation via an insufflation channel 2012 in any port feature may beprovided in some implementations, although as described aboveinsufflation may be provided in other ways, such as via one of thecannulas.) A tether 2014 is attached to cap 2008, and the tether extendsto outside the body.

FIG. 20B shows that the distal ends of the cannulas (or instruments, asapplicable) remain grouped in cap 2008 as it is inserted farther intothe patient. As port feature 2010 remains secure in body wall 2016, thecannulas (or instruments, as applicable) slide through it in order tostay within cap 2008. In some instances the cap is moved farther inwardsby pressing on one or more of the cannulas (or instruments, asapplicable). For example, the endoscope cannula and/or cannula may bemounted on a robotic camera manipulator, and the manipulator may be usedto insert the cap farther inwards.

FIG. 20C shows that once the distal ends of the cannulas (orinstruments, as applicable) have reached a desired depth, the cannulasmay be coupled to their associated robotic manipulators (e.g., cannula2004 a to manipulator 2018 a and cannula 2004 b to manipulator 2018 b).A surgical instrument may then be inserted through one of the instrumentcannulas (e.g., surgical instrument 2020 b through cannula 2004 b, asshown) and mounted to an associated manipulator (e.g., manipulator 2018b). The surgical instrument may then be used to remove the cap from thedistal ends of the cannulas (or other instruments, as applicable). FIG.20D shows that the cap 2008 may be placed away from the surgical siteinside the patient during a surgical procedure using the endoscope andboth robotically controlled instruments 2020 a and 2020 b. Cap 2008 mayoptionally incorporate a specimen bag 2022 for specimen retrieval at theend of the procedure. This specimen bag may optionally incorporate adraw string to close the bag, and the specimen bag draw string mayoptionally be integral with the cap tether 2014. After surgery iscomplete and the instruments, cannulas, and port feature are removed,the cap 2008 (and optional bag) may be removed by pulling on tether2014.

In one aspect, the various mount fixtures described herein areconfigured to aid insertion of and support a combination of one or morecurved instrument cannulas and one or more straight instrument cannulas.

Control Aspects

Control of minimally invasive surgical robotic systems is known (seee.g., U.S. Pat. Nos. 5,859,934 (filed Jan. 14, 1997)(disclosing methodand apparatus for transforming coordinate systems in a telemanipulationsystem), 6,223,100 (filed Mar. 25, 1998) (disclosing apparatus andmethod for performing computer enhanced surgery with articulatedinstrument), 7,087,049 (filed Jan. 15, 2002)(disclosing repositioningand reorientation of master/slave relationship in minimally invasivetelesurgery), and 7,155,315 (filed Dec. 12, 2005)(disclosing camerareferenced control in a minimally invasive surgical apparatus), and U.S.Patent Application Publication No. US 2006/0178559 (filed Dec. 27, 2005)(disclosing multi-user medical robotic system for collaboration ortraining in minimally invasive surgical procedures), all of which areincorporated by reference). Control systems to operate a surgicalrobotic system may be modified as described herein for use with curvedcannulas and passively flexible surgical instruments. In oneillustrative implementation, the control system of a da Vinci® SurgicalSystem is so modified.

FIG. 21 is a diagrammatic view of a curved cannula 2102, which has aproximal end 2104 that is mounted to a robotic manipulator, a distal end2106, and a curved section (e.g., 60 degree bend) between the proximaland distal ends. A longitudinal centerline axis 2110 is defined betweenthe proximal and distal ends of curved cannula 2102. In addition, aninsertion and withdrawal axis 2112 is defined to include a centerlinethat extends along longitudinal axis 2110 in a straight line from thedistal end of the curved cannula. Since the distal section (506 c, FIG.5) of the passively flexible instrument shaft is relatively stiff, itmoves approximately along insertion and withdrawal axis 2112 as itextends out of the distal end of the curved cannula. Therefore thecontrol system is configured to assume that the flexible shaft acts as astraight, rigid shaft having insertion and withdrawal axis 2112. Thatis, the instrument's I/O axis is taken to be the extended straightlongitudinal centerline from the distal end of the curved cannula, andthe system determines a virtual location of the instrument tip to bealong the I/O axis 2112. This instrument I/O movement at the cannula'sdistal end is illustrated by double-headed arrow 2114. To prevent excesslateral movement in the section of the flexible shaft that extendsbeyond the cannula's distal end, in one implementation the extensiondistance is regulated by the control system software and may depend,e.g., on the stiffness of the flexible shaft's distal section for theparticular instrument being used. And in one implementation, the controlsystem will not allow the master manipulator to move the cannula orinstrument until the instrument tip extends beyond the cannula's distalend.

The control system is also modified to incorporate kinematic constraintsassociated with the curved cannula. The motion of the instrument tipextending out of the cannula is described as if produced by a virtualserial kinematic chain of frames of reference, uniquely described by aset of Denavit-Hartenberg (DH) parameters. For example, boundaryconditions for the cannula's distal end 2106 are defined as the tipposition, tip orientation, and the length along the curved section. Asanother example, the boundary conditions are defined instead using thephysical end of cannula, which includes the distal straight section ofthe cannula. Such boundary conditions are used to define the appropriateDH parameters. As illustrated in FIG. 21, a reference frame may bedefined having an origin at a location along longitudinal axis 2110(e.g., at the cannula's remote center of motion 2116, as shown). Oneaxis 2118 of such a reference frame may be defined to intersect theextended I/O axis 2112 at a point 2120. A minimum distance can bedetermined between the reference frame's origin and the cannula's distalend 2106. Various different cannula configurations (e.g., length, bendangle, rotation when mounted on the manipulator, etc.) will have variousassociated kinematic constraints. For instrument I/O, however, theactual path length along the curved section is used instead of theminimum distance between the remote center of motion and theinstrument's distal tip. Skilled persons will understand that variousmethods may be used to describe the kinematic constraints. For example,an alternate way of solving the problem is to incorporate the homogenoustransformation that describes the geometry of the curved cannula intothe serial kinematics chain explicitly.

As described above, there may be two or more curved cannulas withidentical curvatures but various different lengths of distal straightsections. Since the DH parameters associated with each one of thesecannulas are identical, the same intuitive control is maintainedregardless of the length of each cannula's distal straight section.Therefore, since each of these cannulas can be treated identically forcontrol purposes, a cannula-type detection feature as described abovewith reference to FIG. 10 can treat such cannulas as being a singlecannula type.

Further modifications to the control system allow the surgeon to receivehaptic feedback at the master manipulators (e.g., 122 a,122 b as shownin FIG. 1B). In various robotic surgical systems, the surgeonexperiences a haptic force from servomotors in the master manipulators.For example, if the system senses (e.g., triggered by an encoder) that aslave side joint limit is reached or almost reached, then the surgeonexperiences a force in the master that tends to keep the surgeon frommoving the master manipulator in the slave side joint limit direction.As another example, if the system senses that an external force isapplied to the instrument at the surgical site (e.g., by sensing excessmotor current being used as the system attempts to maintain theinstrument in its commanded position), then the surgeon may experience aforce in the master manipulator that indicates a direction and magnitudeof the external force acting on the slave side.

Haptic feedback in the master manipulators is used in one implementationof a control system used to provide the surgeon an intuitive controlexperience while using curved cannulas. For flexible instruments that donot have a wrist, the control system provides haptic forces at themaster manipulators to prevent the surgeon from moving the multi-DOFmaster manipulator with a wrist motion. That is, master manipulatorservomotors attempt to keep the master manipulator orientationstationary in pitch and yaw orientations as the surgeon changes themaster manipulator position. This feature is similar to a feature usedin current robotic surgical systems for instruments with straight, rigidshafts and no wrist. The system senses the instrument type (e.g.,wristed, non-wristed) and applies the haptic feedback accordingly.

Haptic feedback is also used in one implementation to provide thesurgeon a sense of an external force applied to various points in theinstrument kinematic chain. Haptic feed back is provided to the surgeonfor any sensed external force applied to the manipulator (e.g., as mightoccur if the manipulator collides with another manipulator) or to thestraight proximal portion of the curved cannula. Since the cannula iscurved, however, the system cannot provide proper haptic feedback for anexternal force applied to the cannula's curved section (e.g., bycolliding with another curved cannula, either inside or outside theendoscope's field of view), because the system cannot determine thedirection and magnitude of the applied force. In order to minimize suchnon-intuitive haptic feedback for this illustrative implementation,cannula collision is minimized by properly positioning the roboticmanipulators and their associated cannulas, e.g., initially with the useof a fixture and/or during surgery with the use of a port feature, asdescribed above. Similarly, the haptic feedback the system provides tothe surgeon that is caused by external force applied to the portion ofthe instrument that extends from the cannula's distal end will not beaccurate (unless experienced directly along the I/O axis). In practice,though, such forces on the distal ends of the instrument are lowcompared to the amount of friction and compliance in theinstrument/transmission, and so any generated haptic feedback isnegligible.

In other implementations, however, force sensors may be used to providethe surgeon an accurate experience of an external force applied toeither the cannula's curved section or the instrument's extended distalend. For example, force sensors that use optical fiber strain sensingare known (see e.g., U.S. Patent Application Pubs. No. US 2007/0151390A1 (filed Sep. 29, 2006)(disclosing force torque sensing for surgicalinstruments), US 2007/0151391 A1 (filed Oct. 26, 2006)(disclosingmodular force sensor), US 2008/0065111 A1 (filed Sep. 29,2007)(disclosing force sensing for surgical instruments), US2009/0157092 A1 (filed Dec. 18, 2007) (disclosing ribbed force sensor),and US 2009/0192522 A1 (filed Mar. 30, 2009)(disclosing force sensortemperature compensation), all of which are incorporated herein byreference). FIG. 22 is a diagrammatic view of a curved cannula and thedistal portion of a flexible instrument, and it shows that in oneillustrative implementation, one or more force sensing optical fibers2202 a,2202 b may be positioned (e.g., four fibers equally spaced aroundthe outside) on curved cannula 2204 (strain sensing interrogation andstrain determination components for the optical fibers are omitted forclarity). Similarly, the distal section 2206 of the flexible instrumentmay incorporate (e.g., routed internally) one or more strain sensingoptical fibers 2208 that sense bend at a location on, or the shape ofthe distal section, and the amount of displacement and the location withreference to the cannula's distal end may be used to determine theexternal force on the extended instrument.

FIG. 23 is a diagrammatic view of a control system architecture 2300 fora teleoperated robotic surgical system with telepresence. As shown inFIG. 23,

f_(h)=human forces

x_(h)=master position

e_(m,s)=encoder values (master, slave)

i_(m,s)=motor currents (master, slave)

θ_(m,x)=joint positions (master, slave)

τ_(m,s)=joint torques (master, slave)

f_(m,s)=Cartesian forces (master, slave)

x_(m,s)=Cartesian positions (master, slave)

f_(e)=environmental forces

x_(e)=slave position

In one implementation, control system modifications as described aboveare done in the “Slave Kinematics” portion 2302 of control systemarchitecture 2300. Additional details describing control systemarchitecture 2300 are found, e.g., in the references cited above.Control system 2300 data processing may be implemented in electronicdata processing unit 142 (FIG. 1C), or it may be distributed in variousprocessing units throughout the surgical system.

Referring to FIGS. 11A and 11B, together with FIG. 1B and FIG. 4C, itcan be seen that in many implementations, the instrument end effectoractuated by the “left” robotic manipulator appears in the right side ofthe endoscope's field of view, and the instrument end effector actuatedby the “right” robotic manipulator appears in the left side of theendoscope's field of view. Accordingly, to preserve intuitive control ofthe end effectors as viewed by a surgeon at the surgeon's consoledisplay, the right master manipulator controls the “left” roboticmanipulator, and the left master manipulator controls the “right”robotic manipulator. This configuration is opposite the configurationtypically used with straight surgical instruments, in which the roboticmanipulator and its associated instrument are both positioned on thesame side with reference to a vertical division of the endoscope's fieldof view. During use with curved cannulas, the robotic manipulator andits associated instrument are positioned on opposite sides of theendoscope reference frame. This would not apply, however, to the use ofcertain compound curve cannulas, such as is illustrated by FIG. 13 andassociated text.

Thus various implementations of the control system allow the surgeon toexperience intuitive control of the instrument end effectors and theresulting telepresence even without the use of an instrument wrist thatprovides pitch and yaw movements. Movement of a master manipulator(e.g., 122 a, FIG. 1B) results in a corresponding movement of either thedistal end of the associated curved cannula (for pitch and yaw movementsat the surgical site) or the instrument end effector (for I/O, roll, andgrip (or other end effector DOF's)). Accordingly, a surgeon's handmotion at a master control can be reasonably well approximated with acorresponding slave movement at the surgical site without the use of aseparate wrist mechanism in the instrument. The instrument tips move inresponse to master manipulator position changes, not master manipulatororientation changes. The control system does not interpret such surgeonwrist-motion orientation changes.

In some implementations, the control system of a surgical robotic systemmay be configured to automatically switch between the use of straightcannulas with associated straight shaft instruments, and the use ofcurved cannulas with associated flexible shaft instruments. For example,the system may sense that both a curved cannula and a flexible shaftinstrument are mounted on a manipulator, as described above withreference to FIG. 6 and FIG. 10, and so switch to a control modeassociated with the curved cannula and the flexible instrument. Ifhowever, the system senses a straight cannula and flexible instrumentmounted on the manipulator, then this sensing may trigger an illegalstate, and the system will not operate.

In some implementations for surgical robotic systems with multiplerobotic manipulators, the control software can allow the surgeon to usea mix of curved cannulas of various different shapes, flexible shaftinstruments of various different lengths, together with straightcannulas and rigid straight-shaft instruments. The tip motion of allsuch instruments will appear alike, and so the surgeon will experienceintuitive control because of the automatic handling of the cannulakinematic constraints as described above.

We claim:
 1. A robotic surgical system comprising: a rigid cannulacomprising at least a portion that has a curved longitudinal axis; and asurgical instrument configured to be advanced through the cannula, theinstrument comprising: a proximal end transmission mechanism, a distalend surgical end effector, and a shaft that extends from thetransmission mechanism to the surgical end effector, wherein thetransmission mechanism comprises a force transmission interface to arobotic manipulator, wherein the shaft is passively flexible, whereinthe shaft comprises a push/pull drive element positioned along alongitudinal centerline of the shaft and at least three force isolationelements spaced equally around the push/pull drive rod, wherein theforce isolation elements isolate the push/pull drive element frommovement as a result of a bending of the shaft as the shaft translatesthrough the cannula, wherein the end effector comprises a movablecomponent, and wherein the push/pull drive element is coupled to themovable component.
 2. A robotic surgical system comprising: a rigidcannula comprising at least a portion that has a curved longitudinalaxis; and a surgical instrument configured to be advanced through thecannula, the instrument comprising: a proximal end transmissionmechanism, a distal end surgical end effector, a shaft that extends fromthe transmission mechanism to the surgical end effector, the shaftcomprising a push/pull drive element and a plurality of force isolationelements, wherein the transmission mechanism comprises a forcetransmission interface to a robotic manipulator, wherein the endeffector comprises a movable component, wherein the shaft is passivelyflexible and comprises a support tube, wherein the support tubecomprises a central channel and a plurality of force isolation elementchannels around the central channel, wherein the push/pull drive elementis positioned in the central channel and is coupled to the movablecomponent, wherein one of the plurality of force isolation elements ispositioned in a corresponding one of the plurality of force isolationelement channels, and wherein the force isolation elements isolate thepush/pull drive element from movement as a result of bending of theshaft as the shaft translates through the cannula.
 3. The roboticsurgical system of claim 2: wherein the transmission mechanism comprisesa roll drive element coupled to roll the shaft within the cannula. 4.The robotic surgical system of claim 2: wherein the support tube furthercomprises at least one flush channel around the central channel.
 5. Therobotic surgical system of claim 2: wherein the support tube extends forsubstantially the length of the shaft and comprises an isotropicmaterial.
 6. The robotic surgical system of claim 2, further comprising:a memory; and an interface between the memory and the surgical system;wherein the memory comprises kinematic data associated with the cannulathrough which the shaft extends.
 7. A surgical instrument comprising: aproximal end transmission mechanism, wherein the transmission mechanismcomprises a force transmission interface to a robotic manipulator of asurgical system; a distal end surgical end effector comprising a movablecomponent; and a shaft that extends from the transmission mechanism tothe surgical end effector; wherein the shaft is passively flexible;wherein the shaft comprises a drive element coupled to the movablecomponent of the end effectors; wherein the shaft comprises a forceisolation element rod; and wherein the force isolation element rodisolates the drive element from movement as the result of a bending ofthe shaft as the shaft translates through a cannula having a portionwith a curved longitudinal axis.
 8. The surgical instrument of claim 7:wherein the transmission mechanism comprises a capstan; wherein thedrive element comprises first and second tension elements coupledbetween the capstan and the moveable component; wherein rotation of thecapstan in a first way pulls the first tension element to move themovable component in a first direction; and wherein rotation of thecapstan in a second way opposite to the first way pulls the secondtension element to move the movable component in a second directionopposite the first direction.
 9. The surgical instrument of claim 7:wherein the transmission mechanism comprises a slider coupled to arotating element; wherein the drive element comprises a push/pull driveelement coupled between the slider and the moveable component; whereinrotation of the rotating element in a first way pulls the push/pulldrive element to move the movable component in a first direction; andwherein rotation of the rotating element in a second way opposite to thefirst way pushes the push/pull drive element to move the movablecomponent in a second direction opposite the first direction.
 10. Thesurgical instrument of claim 7: wherein the transmission mechanismcomprises a rack and pinion engaged with one another; wherein the driveelement comprises a push/pull drive element coupled between the rack andthe moveable component; wherein rotation of the pinion in a first waypulls the push/pull drive element to move the movable component in afirst direction; and wherein rotation of the pinion in a second wayopposite to the first way pushes the push/pull drive element to move themovable component in a second direction opposite the first direction.11. The surgical instrument of claim 7: wherein the shaft comprises aflush tube and a chamber at a distal end of the shaft; and wherein theflush tube is configured to flow flush fluid distally within the shaftthrough the flush tube and the chamber is configured to redirect theflush fluid to flow proximally within the shaft around the driveelement.
 12. The surgical instrument of claim 7: wherein the driveelement comprises a push/pull drive element having an unconstrained rolldegree of freedom that isolates the push/pull drive element fromrotation of the shaft.
 13. The surgical instrument of claim 7: whereinthe shaft comprises a middle section and a distal section; and wherein astiffness of the distal section is larger than a stiffness of the middlesection.
 14. The surgical instrument of claim 13: wherein the shaftfurther comprises a stiffening element that extends within the distalsection and not within the middle section.
 15. The surgical instrumentof claim 7: wherein a stiffness of the shaft is effectively constantalong the length of the shaft.
 16. The surgical instrument of claim 7:wherein a rotational stiffness of the shaft is in the range of about 11lb-in² to about 66 lb-in².
 17. The surgical instrument of claim 16:wherein the rotational stiffness of the shaft is about 22.0 lb-in². 18.The surgical instrument of claim 7: wherein the surgical instrument is anon-wristed instrument.
 19. The surgical instrument of claim 7: whereinthe drive element is positioned along a longitudinal centerline of theshaft; and wherein the surgical instrument comprises a plurality offorce isolation element rods spaced equally around the drive element.20. The surgical instrument of claim 19: wherein the plurality of forceisolation element rods comprises three force isolation element rods.